Reason #3,295 for having a can of naphtha around the house: to clean the glue off your chest that those pesky ECG sensors leave on your skin :laughing7:
Hope your heart is not a cause for concern.
Depending on your painting skiills/habits, a gallon of lacquer is good for 3 to 5 solid body finishes.
Typically, with lacquer, the cost of materials for a finish isn't how you decide whether to pursue that on your own or have it done. It's the amount of labor involved. Lacquer is one of the more labor and time intensive finishes you can apply. That's why nearly all manufacturers have gone to polyurethane. It's almost a "shoot it and forget it" finish, while lacquer is a shoot it, do some surface prep, wait, shoot it again, do some surface prep, wait, shoot it again, do some surface prep, wait, shoot it again, for some number of coats, then wait a long time and do some more intensive surface conditioning before you have a finished product. Costs a lotta hours.