If you’re just wanting to practice building the position, pulling the trigger, and managing the recoil then any brands “match” line would work okay. But if it works for practice it should work in the game, right?
You’re best bet may be to continue to use FGMM for practice so you know if you’ve missed or hit that it was you and not the ammo. If you aren’t getting good feedback from your practice then you may not progress the way you want to. You set up, feel stable, have everything lined up. Good trigger control and breathing, but the shot misses. Why did it miss? Did you flinch or was it sub par ammo? What can you learn from that shot?
You may get to shoot a little more but it may only save you $4-5/100 rounds and you may not get the training like you had hoped.
Look on ammoseek.com to find the best price. I know Palmetto State Armory will have it for about $16-17 per box pretty often.