Check the resale shops, theres a lot of tables that can be used for a sewing table. Depending on the room you have, a small kitchen table would work. I have my mother in laws old singer cabinet, with a piece of glass on top of it. I placed my embroidery machine on this 'table' and it works great. Buying a 'sewing table' will cost more.
The possibilities are endless, just start looking around. Know the size you want, and the height you need.