If you really really want to buy your own tool I'd give this kit a close look.
The linked kit I found under the brand names Wonderman, Sealey and Neilsen, and I found it on eBay.co.uk for as much as about £120 and as little as £45 with free (UK) postage, so a fifth the cost of the Wurth timesert kit. It uses the same kind of system though:
- a step tap , 14mm to screw in to any remaining thread and hold the larger tap straight,
- a seat cutter with depth stop that slides over the tap shank and cuts a seat for the lip of the insert.
- It uses a different but neat insertion tool, where a lock nut is undone, removing a driving packer/tube and removing any load from the threaded portion of the tool, allowing it to be unscrewed without the insert backing out
- a 14mm tap which is run through the insert after fitting. I haven't found details on this tap and the inserts, but I'm guessing it's swaging/cold rolling the final threads on the insert like the Wurth kit does.
It's a fifth the price, something probably isn't so good, but I'd try it for a saw if I really wanted my own tool
