What StartingOver10 suggests is certainly the most straightforward and extensive way to get all three of your scores. It does cost money, though. But if you're preparing to apply for a mortgage or something else significant like that, it probably makes sense.
An alternative is that certain credit cards and I believe some credit unions offer free FICO scores. I get a monthly Experian FICO 8 from American Express and a TransUnion from Discover. If you have just one of those, then something like Credit Karma can be useful -- not for the score it offers, but just to make sure that nothing is going wonky with the CRAs it monitors.
I don't know that I'd open a card just for the free score, but it's nice to have if the card makes sense for you otherwise.
