Besides searching for a deal on a regular single purpose tiller, and I have also been looking at tiller attachments for my Troy Bilt weed whacker. I was surprised at the variety that are available. I am guessing that most of them are all actually made by the same company, and are just painted different colors, and labelled differently. Last night on eBay I bid on a Troy Bilt TBGC cultivator, but was outbid. I was also watching an auction for a Poulan Pro PPB2000T tiller attachment, which looks exactly the same as the Troy Bilt TBGC, except a different color and label. But unfortunatly, I missed bidding on it. I was at karate class, and didn’t get home in time. It ended with a bid of $51, and shipping of $20. It was new, and would have been a good deal maybe if the bidding didn’t go too much high. Oh well.

Here is a list of compatible tiller attachements:
Troy Bilt TBGC
Poulan Pro PPB2000T
Ryobi GC720R
Weedeater 2000T
Expand-It UT15550
Chicago Electric Power Tools Tiller Attachment (Harbor Freight Tools)

I think that all might be the same, with the exception of the Expand-It UT15550, which looks different than the others.

The one at Harbor Freight is only $70, as opposed to the others which go for $90. But I would be leery of the one from Harbor Freight breaking.