Even if you mask them yourself, it's still not the same. You can't buy (well, maybe somewhere you can) the same application tape they put on pinstripe tape. And you're not likely going to be premasking and then cutting your stripe and backing paper all in one fell swoop. The clear premask they use on pinstriping tape lets you bend beautiful curves, follow contours, yet also allows you to pull straight stripes 10' long, snapping it up if you need to reposition. Then after pressing it down, it is easy to remove without disturbing the new stripe. The paper application tape we all have on hand cannot do that. A 150' roll of 1/4 to 1/2" tape, whether a single stripe or double stripe, is going to retail for $70-$120. It's money well spent if you're pinstriping a car, even if that car is only 16' or 20' long.