How much money should I take with me on vacation?

I was just at Hogsmeade in Islands of Adventure in April (and sad that I missed out on Diagon Alley)

so if you're just planning to get souvenirs at WWoHP, I'd suggest taking $100-200. The pre-made wands based on the HP characters are 35.00. I believe the Ollivander Wands (where the "wand chooses you") are anywhere from that price and possibly higher.

Honeydukes in Hogsmeade has a lot of the novelty candies and I'm made that I didn't get a chocolate frog (7.99 I think) or any of the other candies (5.00-50.00 depending on the size of the box and what it is - possibly even more I can't remember)

Otherwise there's everything and anything HP related like t-shirts, stuffed owls, blank journals, scarves (house colors), Marauders' Maps, etc.

It's really up to you what you want to buy because only you know what you'll like but you should always take more than you expect to spend because if you're like me you'll hate having to try to decide what to get because you want it all but can only afford one.

And why wouldn't you "waste" money on a few souvenirs?! I love my Elder Wand - it sits in it's opened box on my curio with all my figurines and it reminds me of my trip just as much as the pictures. Matter of fact, I'm regretting not getting MORE souvenirs because now I just have the wand and brought back a load of money instead (which was nice to pay bills with but I wish I'd bought a tshirt)

Enough for one item, probably a t-shirt. But first, in the circles where you travel, is it going to be OK to wear a Harry Potter t-shirt? I throw on my Mickey t-shirt on the weekends, but I am what you would consider an old guy, so who cares? On the other hand, I really don't think I would wear a Potter t-shirt.

I think buying wands is pretty silly for anyone over the age of about 6. But, they sell the heck out of them. I guess you need to ask yourself if you will be embarrassed to admit that you bought the item when you get home.

Have fun on vacation.

Take as little as possible so you do not waste it all on souvenirs. Set a budget (you can probably do some research online) and only buy a few items. You will find that most of what you buy will sit on your shelf (or in your closet) and will not be used or looked at much at all. Nothing there is rare and if it were it would only be a "fake" rare item, as they are selling the stuff to thousands of people daily. A better idea would be to enjoy the trip as much as possible and just have fun. Since your parents are paying for all the real expenses (travel, lodging, tickets to the parks, and probably food), you will need next to nothing. Buy a t-shirt you like and leave it at that. Five years from now anything that you bought will become irrelevant. And DO NOT buy stuff for your friends - that is a colossal mistake many people make.

It's really hard to say because it depends on what souvenirs you want, and how many of them. You could buy one or two small things with $20-30. Or you could buy one or two big things and spend $100 or more. Take what you can afford to spend, and buy within that budget when you get there.