re: how much to pay someone to help out at a party?

I did essentially the same thing last fall for a wedding. Granted, it was probably a bit more demanding than what you are wanting. It was me and another person, and we setup the entire reception, broke it down, replenished food, drinks, etc. Helped in the kitchen, served people if they needed help, helped the band setup/pickup.

We each got $100 for working 6-11. If they do a good job, make sure to give them a little extra. We were only supposed to help in the kitchen and replenish food and drinks. We ended up doing extra work than what was asked and was asked to stay a couple hours later than the agreed upon time ~1AM or so. Was bummed we didn't get a tip or anything, but was still happy to make $100 for a night's work.

Only you know how demanding the tasks are. So, if you were doing this stuff for someone's party, what would you want to be payed? $60 might be enough for the work itself, but you are hiring a person that will be an essential aspect behind the party going smoothly. This person will also allow you to be more of a presence at the party and have yourself a good time. All of that is worth more than $60 in my opinion.