BMX weed eater cost without welding or bolting?

Ok so I have a new weed eater 25cc I got it and forgot we already had one but I have a bmx bike and I want to put it in it from direct drive (cheapest) without welding my limit is 30$ don't wana go over that I wana put it on to run it at max RPM'S and I have a few leftover bottles of Nos from my dad's car to just blow it up so plzz answer