The only single band one for 40 meters that I know of that is available new right now is the MFJ-9440. Each model is a bit over $300 (prices vary by band for some reason), which feels like a lot to me for what you get.
Single band SSB rigs for 40 that have been available in the fairly recent past include the Bitx 40, Easy Bitx (returning soon in an updated version), and Pacific Antenna MMR-40.
Multiband rigs that can do SSB that are currently available include the Elecraft KX2 and KX3, Xiegu G90, X5105, and G1M, Radioddity QR20, Icom IC-705, Yaesu FT-818, uBITX, and more. The G1M and uBITX qualify as inexpensive (in the $200-$300 range).
If you are feeling adventurous, there are also some kits from Russia and China.