Living here in the Sonoma/Napa area, my daughter works for a higher-end winery and brings home an undrinkable amount of wine, so much we have cases and cases of it stored everywhere and most are $50. to $200. bottles. Yes, spoiled.
It wasn't until she started working for a winery (and getting free wine) that we started bringing bottles of wine to restaurants. I think the average corkage fee we pay around here is between $10. and $15. and of course in this area restaurants are use to people (mostly tourists) bringing in bottles.
For us, paying a $10. corkage fee is still a great deal compared to what we would typically pay for drinks. As for leaving a reasonable taste for a waiter being considered proper etiquette, I've never heard or seen that before. And I would assume not legal, at least here in California.