You can use any lower handguard as long as it does NOT have a vertical grip. This will turn a pistol in an AOW, requiring prior approval from ATF on a Form 1 and a $200 tax. Now that that's out of the way...
There's no requirement for U.S. made parts on a pistol, so imported sets are usable. Check in the Equipment Exchange to see if anyone has a set for sale. You may be able to pick up a cheap set from someone that swapped them out for U.S. made parts.
Polymer handguard sets from K-Var are a little on the expensive side ($50+ for the pair). They do have Romanian upper and lower solid wood pieces that would be about $30 for the pair. Romanian laminate will be around $40 for the pair.
You can get a pair of Polish laminated handguards from Global Trades for around $30.