Oh bugger. Can't really offer much in the way of suggestions here. The coil insert kits average around $50 for each thread size, in the smaller sizes we're looking at here, last time I looked.
In former times, many areas had a semi-retired old bloke or two [machinist/toolmaker or mechanic], who would do such small jobs cheaply, and had the gear to do so. They were usually hard to find though, as they didn't advertise, and word-of-mouth was the only way.
My motorcycle mechanic operates like that; he just has a single line in the Yellow Pages, and even when you find his place [outside of town], there's no signage visible from the dirt road he lives on. There are one or two local car mechanics [very good ones] that work the same way. More than a few visiting city types have been gobsmacked to see the gear in his shed though. The full nine yards for bike work, including a Dynojet dynamometer with exhaust gas oxygen monitoring!
