Best semi-firm twin mattresses under $500

Top pick: Beddle 12" Gel Memory Foam, Medium Firm (twin). It's the clearest semi-firm twin here — a medium-firm gel foam build in a 12-inch profile, so it gives support without the sink of a soft foam bed, and it's rated well by buyers. Best all-rounder for a guest room, teen's room or a sleeper who wants a bit of firmness.

Who the others suit:

• lemontalking 14" Hybrid (twin) — if you want a hybrid: pocket springs plus gel foam, medium firm, and the thickest of the group.
• Atlas 12" Innerspring (twin) — if you prefer a traditional spring feel with a firm-ish surface.
• Avenco CozyNest / Pearl 8" (twin) — budget-friendly medium-support innersprings for a light-use or occasional bed; thinner, so less cushioning.
• FDW 6" Gel Memory Foam (twin) — for a bunk, trundle or very tight space where height matters.

Skip the queen-size and non-mattress items in the list — they don't match a twin semi-firm ask.