I use Vantage scores as a general measure of my credit health, but the scores are not reliable or relevant in the real world. As others have said, you need FICOs if you want to know what your scores are that lenders will see.
The best place, obviously, to get your FICOs is from this website. For $60 (or whatever the current cost is), you can get ALL your credit scores that a lender would see. Not just your FICO 8, but also your FICO 8 Bankcard, Fico 8 Auto, FICO 9, FICO 5,4&2 (used in mortgages), from all 3 bureaus.
This is literally THE only website where you can get all those scores.
Alternatively, you can piece-meal it from other websites, with varying degrees of difficulty. For example, you can get a free Experian Fico 8 from freecreditscore.com. You can get a free Equifax FICO 8 Bankcard if you have a Citi credit card. You can get a few other FICOs at other various bank websites and such. But the easiest way is to get them all from one place - here.
What I used to do (before I signed up for a monthly account with MyFICO), was buy a 3-bureau one-time report from MyFICO, so that I at least knew what all my scores were at that moment, and then for the next few months I'd just track my Vantage scores to see whether or not my scores were going up or down. Pay no attention to the scores themselves, they are useless... but you can at least use them to gauge whether or not your credit is getting worse or better with time. And then occasionally I'd buy another MyFICO 3-bureau report to verify where I stood. Maybe that strategy would work for you, too.
These days, I just pay my $40/mo and get all 15+ FICO scores updated every month, and call it a day. For me, it's worth the money to know precisely what a lender would see if they pull my scores. Otherwise, if you want to save money, you can sort of "ballpark guess" it with the other strategy above.
Total Loan Balance: $43k / $65k
Total SL: $78k
I appreciate the honesty. I remember previously paying for the a monthly monitoring, don't remember if it was a correct website. That was when I had less at steak too. I am also not against the jumping around to know my fico scores, being an increasingly valuable number. I am increasingly reinvesting into my credit as it is growing. I will be thinking of doing sooner rather than later now that there is actually a way to know how to improve 
(I'm not a MyFICO employee or shareholder, though I might sound like it haha!) but I gotta say, while $40/mo is a lot of money, it's worth it when you're on a rebuild journey. Unless, of course, the money is better spent on handling derogatories.
Personally, there are 2 things I always recommend to people who are rebuilding their credit and/or finances... Quicken, and MyFICO. Those two tools are my biggest weapons for keeping my finances and credit on track.
Regarding MyFICO, its worth is in the fact that you know EXACTLY what scores a potential lender will see, before you apply. So you can time your applications perfectly to achieve the best terms. For example, I plan on refinancing one of my cars soon, so I've been tracking my Fico 8 Auto scores the last few months. I'll know exactly the right day to apply for the refinance, because I know what my target score is and I'll know exactly what day I'll achieve that score.
Beats the heck out of playing the guessing game!