First off, welcome to the forum. I challenge anyone to try and find a better resource for rebuilding. Won’t happen - this site is a gem on the web.
You can rebuild your credit with the techniques and advice you’ll find here. It takes time and perseverance but any pit of credit hell can be recovered. There are people here who started in the 400s who are now over 800 and rocking six-figure aggregate credit limits.
As to what you need:
It takes six consecutive months of reporting to generate a FICO score. The ideal minimum mix in order to achieve a good score is proper management of 3 revolving accounts and one loan. You have the loan and one card in hand now. Ideally you’d add two more cards and then maintain them. You could do the prequals for a Capital One secured card, but the downside to that is that they no longer graduate into unsecured cards like your Discover will. Still, it’s a card to add to the mix. You might also look at OpenSky, as they issue secured cards with no credit check, which is good because you don’t really have a score to check. Those would give you your mix of 3 cards and a loan.
From there, just garden - tend to your cards, keep your usage low, and never, ever miss a payment or pay late. Look up “AZEO” on here for how to implement the All Zero Except One method to maximize scoring, and put that into practice.
As for the collection amount, when did it go into collections, who currently owns the debt, and what is the date of first delinquency (the DoFD, the date at which it went delinquent and never recovered)? This is key info to help you chart a course. Disputes can work if the debt can’t be validated but in reality, they aren’t meant for removing items on your reports that are legitimate. If you can provide that info, it’ll help us help you. Make sure to include all relevant info and don’t worry about how it may look to others in your eyes. There is NO judgment here, as many or most of us have been there and done that. Life happens and we get it. This place exists in large part to help people in your situation (which was basically me as well, less than a year ago) rebuild and solidify their financial futures.
Fill us in on the details and we can get you pointed in the right direction
You can rebuild your credit with the techniques and advice you’ll find here. It takes time and perseverance but any pit of credit hell can be recovered. There are people here who started in the 400s who are now over 800 and rocking six-figure aggregate credit limits.
As to what you need:
It takes six consecutive months of reporting to generate a FICO score. The ideal minimum mix in order to achieve a good score is proper management of 3 revolving accounts and one loan. You have the loan and one card in hand now. Ideally you’d add two more cards and then maintain them. You could do the prequals for a Capital One secured card, but the downside to that is that they no longer graduate into unsecured cards like your Discover will. Still, it’s a card to add to the mix. You might also look at OpenSky, as they issue secured cards with no credit check, which is good because you don’t really have a score to check. Those would give you your mix of 3 cards and a loan.
From there, just garden - tend to your cards, keep your usage low, and never, ever miss a payment or pay late. Look up “AZEO” on here for how to implement the All Zero Except One method to maximize scoring, and put that into practice.
As for the collection amount, when did it go into collections, who currently owns the debt, and what is the date of first delinquency (the DoFD, the date at which it went delinquent and never recovered)? This is key info to help you chart a course. Disputes can work if the debt can’t be validated but in reality, they aren’t meant for removing items on your reports that are legitimate. If you can provide that info, it’ll help us help you. Make sure to include all relevant info and don’t worry about how it may look to others in your eyes. There is NO judgment here, as many or most of us have been there and done that. Life happens and we get it. This place exists in large part to help people in your situation (which was basically me as well, less than a year ago) rebuild and solidify their financial futures.
Fill us in on the details and we can get you pointed in the right direction
Welcome, @Anonymous.
At this point, I'd let FICO scores generate. That'll guide you on the next app. With a clean file, six months with a secured Discover card would position you for a good unsecured product as your next card. With the baddie, the scores can help guide you on your next course of action.
I agree with the idea of three cards. But there's no rush to obtain them. On the other hand, acquiring them too quickly can cause problems. I'm a fan of a card once every six months, e.g. month 1, month 7, month 13, month 19, and month 25.
Try doing this this is what I did starting out and it greatly helped me! Use as high as you can on your card, pay it all down to 0 for your payment then put a very little bit before your statement hits that way it shows usage and responsible use too! This will help with jumps in score as well as CLI you also want to keep up with your AAoA's a year plus is GREAT so don't apply for one card, then a few months later get another then a few months later apply for another that will be horrible to your build and you want to keep your inquires if possible a minimum 6 months apart!! If you can if you have a secured card work on that for a whole year then try to upgrade to an usecured with a higher limit and apply for 1 or 2 cards at the time they pull your information to see if you can update to an unsecured from your secured that is exactly what I did and it did drop my score at first BUT in a month's time my score bounced back 30+ points so it won't stay down long then I would recommend doing another year and in the meantime depending on the card or cards you pick do CLI only if it's a SP!!! If you can do NOT touch them for another year just to help build back up your AAoA's I mentioned earlier. The longer that is the less drops you will have and it will help you in the future! Good Luck and we are all here to help!
You want to be 5 dollars or more on your card though as sometimes lower will just be forgiven and no more than 8.9% across all cards to keep in line with the AZEO method 
You can use the whole 200 I actually recommend using as much as you can during the month as long as your payment comes you pay it down to 0 and then put the 5 dollars or 13 dollars or whatever the case may be before the statement hits then wash rinse and repeat! If certain cards see you are not using your amount they may lower your amount or deny you a CLI because they see it as you don't need/use that much! So don't let it bite you in the tush!