Installing can lights? If you know what you're doing, I wouldn't bother with a permit. Adding an attached deck to the back of the house? Yeah, that's worth pulling a permit.
In our municipality, permits cost 1.25% of the project cost, with a minimum amount of $80. That fee also covers the cost of inspection. If you're doing something simple like putting in an outlet and you're only spending $20 on materials, spending five times as much just to get an inspector to sign off on something you know to be correct is silly.
A lot depends on your local government's building dept. Mine has some really lame rules (like no romex or PEX), but otherwise have been great to work with, and are concerned with things being done correctly, rather than increasing revenue.
Generally, the reason a municipality wants you to get permits is so they can ask how much the projects costs, then jack up your home value for taxation purposes.
So long as you know what you are doing, I sure as heck would not involve the my municipality to simply install a couple lights.
This very much depends on your location. Where I'm at, the local building department is run by the village, while the tax assessments are run at the county level, and the two don't talk to each other. I'm also in a master-planned subdivision, and all 100 houses are one of five floor plans, all built by the same builder, all on the same size lot, all fairly close in square footage. So our tax assessor looks at the average of recent sales and adjusts based on brick vs vinyl, whether you have a lookout/English basement, etc. Interior finishes or even a finished basement aren't considered.