Boris - I have been going to Vegas for 40+  years - I still go - and these are the parking venues I use - (1) Golden Gate valet - requires a modest tip , (2) Fremont Hotel and Casinno - valet, requires a modest tip, (3) the 4 Queens - park in the garage, get ticket, go into the casino, sit at a machine and press the service button. A tech will come and verify your ticket which will allow you to exit the garage at no cost, (4) - El Cortez use the valet, pay with a modest tip. You can park at any/all of these places for an extended amount of time for next to nothing. I recommend the Fremont because it is centrally located - easy in and out.