I've stayed myself in a hotel in Bangkok for 20$/night,
it was September so probably low-season rate, and I bargained a bit
since I was staying a week. The room was equivalent to a north american
"Days Inn". The staff were chinese and didn't speak too much english.
I'd give the hotel 2 or 3 stars, it's not the Oriental hotel of course
but for a tourist on a budget it's decent.

I don't know the name (it's a chinese name) but from the "world trade
centre" go north across the canal, go west on the next major road, and
north on the 3rd or 5th soi. There's an electronics shopping center, a
market, and a very tall (Bayoke II?) hotel nearby.