getting comp upgrades

[Deleted]

 .

Have any of you slipped $ to get an upgrade when checking in a hotel?

I read about it on sites like Trip Advisor but have never done it myself. We are heading to Vegas this weekend and am wondering if I should try it.
If you have tried it , does it work? Have you been turned down? 

[zitiqueen]

Try it. The worst that will happen is they say no.

[sarahsas]

You can always ask without money and they may even give it, then you tip. When I went, I didn't ask for an upgrade because I had to have a certain type of room, but I was really friendly to the lady checking us in and talked about how it was my first time in Vegas and how excited I was, and she comped me two free passes to an attraction and two free buffets.