Cheapee Impact Stickers
Go to your local print shop and ask them for scraps of NCR paper. Tell them you want the remains of their "CFB" sheets. This is carbonless paper for business forms (NCR = no carbon required), and you want the middle sheets, the ones that are coated front and back (hence the CFB designation). 1" x 2" rectangles are what I use. If they have it, they will probably give you cutter scraps for free. If not, a few dollars should buy enough paper for hundreds of stickers.
If you have to buy as much as a ream, they will probably charge you something like $10 plus a few bucks to cut it for you, but the cost per sticker is virtually nil. If you make them the 1" x 2" size I use, you can get 22,000 pieces out of a ream.
Then trundle over to the nearest art supply store and get a can of "spray mount." This is the aerosol equivalent of that semi-sticky stuff they use on Post-It notes. Costs about $5.
Now, take a piece of the NCR paper, mist it with the spray tack. Wait about 3 secs for the adhesive to get tacky, then stick it on the clubface. Doesn't matter which side you stick to the club. Go strike a ball.
This will give crisp blue/purple impact marks as good as the impact strips, and is sensitive enough to show a mark for all shots with the possible exception of the gentlest of putts.
Burgess