Welcome!

As you mentioned could be warped discs or sticking caliper.

Mr2' s are renowned for sticking calipers.

I have a folder of receipts for new calipers over the years.

The pistons stick inside

(dirt gets into the rubber and they seize.

If you are lucky it could be just the sliding pins.

Take them out and grease them up.

Very easy fix.

You won't know til you take wheel off and turn disc.

There should be very little resistance.

Other thing it could be is wheel bearing.

Jack car up with wheel still on and shake left to right and top to bottom.

Any movement will be wheel bearing or ball joint/track rod end.

I bought mr2 turbo last jan and replaced all front suspension

(ball joints, inner/outer track rod ends, drop links.

Bushings were ok.

They were all original parts so needed changed after 20 yrs lol

Might be worth checking all of above if you've just bought it.

Also everyone will tell you on here that mr2's are very sensitive to ignition components

(distributor, rotor arm, spark plugs, ht leads) although my ht leads are still marked 1992 and are 100%)

That's my 2p worth.

These cars are bullet proof and super reliable if you service them regularly.

Happy motoring!