I hate to say it, but you may be setting yourself up for dissatisfaction if you want a cheap phone for gaming. The problem is that cheap phones typically have little internal storage, and that's important if you want to install a lot of games or large games. It doesn't matter if you can add a microSD card, because you typically can't install apps to the removable card.
In general, you want to look for a phone that has at least 8 GB of internal storage, because if it has 4 (which is common with these cheaper pay-as-you-go phones), you'll end up with only about 2 GB or less of storage you can actually use, and that's not much. If you're finding it hard to discover how much storage a phone has, search for it on a site like phonescoop.com.