What kind of substrate for bottom feeders?

just find a substrate that is kind of small but not too sandy because the pleco might choke when on the ground, corries need a soft substrate to scavenge for food so sand would be best for them. The only problem of this matter is that this kind of sandy like gravel is VERRRY expensive, $20.00+ I hope this is helpful and I wanna no how the tank turns out

As long as it's smooth and rounded, regular gravel should be fine for your corys. Just don't use anything thats like broken up chips of any thing, or sharp edged.

i would use aquarium sand.