check this
patio heater out, on sale at Costco, the tank top heaters are OK, but the heat goes up and not very far out. The patio type reflect heat down and seem to work a bit better.
edit: apparently I can't read, you wanted one for under $100 and the patio design is probably not what you are after, but I'll leave the post anyway in case someone can benefit from the sale at Costco.