Regarding "cheap and plentiful ammo" only use it if your gun shoots well with it, otherwise trade it off/sell it, toss it in the lake if it truly is an ammo issue.
Using ammo that is weak in your gun, such as FTF, FTE-stovepipes and such has several dangerous issues.
Just off the top of my head...
1. Clearing a jammed firearm increases the possibility of an accident. particularly when you get frustrated after several FTE.
2. That said, it spoils a great afternoon of shooting. Also can dampen the interest and raise anxiety of a new shooter. Though it is a good lesson in clearing a firearm malfunction if done safely, but still no fun if you have to do it with every magazine.
3. Gives the gunowner doubts about the reliability of his firearm.
4. May be unsafe if firearm is considered for defensive purposes, you don't want a malfunction in a self defense situation.
once you try other ammo, and problem goes away, likely gun just doesn't like that flavor. If it persist, load the mag with 7 rounds and see how it performs- do this several times, then load with 5 rounds and check performance with several 5 round mags. If it peerforms well with 7 or less rounds likely the mag spring should be replaced.
I have an old remington 510T .22 bolt an rifle with an old mag that hates 10 rounds, but loves 7 rounds.
I need a new mag for it but hard to find.
Anyway just some ideas to start with. And like I said, cheap ammo is not a bad thing. Unless it creates an unsafe situation....
NVCZ