Some good advice after my favorite tool purchase of last year:
The helicoil kits are kinda pricey, mostly due to the cost of the single
size-specific tap.  Go out and buy yourself an entire tap and die kit from
sears, etc. Buy the largest metric kit you can afford, but $75 gets you a
decent start.
I use these all the time- not just for helicoils(inserts are cheap to buy-no
need for the "kit" now)--but I use them on nearly EVERY nut, bolt, stud, and
fastener that I remove from my aging vw's.  I quickly clean up the threads
to like new condition before reusing them.
Try this and you will be amazed at how nice it is to work with your
"reconditioned" bolts, etc. This will also save you many trips to the
hardware store looking for those metrics in size "x".
Indiana Jay