want to buy: cheap complete search extension for 1.5.4

hello.
i want to buy a good and cheap search extension for version 1.5.4.
most imporant thing is to search partial, so if i search for the word "good" it has to show results like "goodness", OC cant do it per default. Also very important is to search in product description. smart search and auto complete would be good but arent that needed.
Thanks for answers.

Smart Search can do all that, but I wouldn't call it "cheap".

hi,
i think the partial search opencart can in basic version
http://demo.opencart.com/index.php?rout ... r_name=iph