If you are a guy and you are reading this, then I urge you to think about the cost, and about how much you're willing to pay, and I hope that your decision will include paying for more than the few items discussed below. My recommendation is that in addition to these items, you also take a look at the next section, "What's Split," and consider paying for the whole thing. I say this because we almost always forget that in addition to splitting the cost of prom night, your date also has to get her dress, get her hair and other things done, get accessories, and get a few other essentials. This adds up, you know, and if she also has to split the cost of the night, she could end up paying overall as much as four times more than you--and that is not fair, not if you're a gentleman, anyway.
The average price for tuxedos is not easy to determine because they are priced by style. Classic, or more conservative tuxedos range between $65.00-$95.00, depending on where you rent.
Designer labels or more exotic tuxes--a Verdi 5 button by Fumagalli or those popular zoot suits that began to appear in Spring 2000 and are still going strong--will start at about $115 and can range up to $200.
Renting the tux, however, means a bit more than the suit. You will also need shoes, shirt, and jewelry (cufflinks & studs). This is usually part of the tux rental package and the store attendant will ask you which items you need and show you what they have. If this is your first time renting a tux, then just let the attendant know this, and that you want whatever is appropriate. If you don't know how to put on the links and studs, for example, ask them to show you how in the store.
Finally, you will need a tie and cummerbund, or a full back vest. Depending on the tux style you have rented, the tie may be a bow tie, or it may be long. If you are not wearing a cummerbund, then you must wear a vest. Sometimes, you can order either the cummerbund or the vest in colors that match your date's dress. It is slightly more expensive than the standard cummerbund or vest-- about $20.00 more--but the final effect is well worth it.
Is there any one style which is more appropriate than another? The answer is no. You wear what you like, as long as it's a tux and it's not a "morning coat" (the classic dinner jacket is just fine). Or, you don't wear what you like because you have to wear what your date likes--but that's between you and your date.
What is this corsage thing, anyway? Well, it's between $18 and $35, and technically, it's just a couple of flowers with some leaves and maybe a spray of something that looks like it was picked in a field. But that's not the point. The point is that it's an important part of the prom tradition in that you present your date with her corsage when you first arrive to pick her up. Giving a corsage (and flowers in general) has a ritual dimension: it shows that you consider that person special and that you are singling them out to enter into a special relationship with you, even if this relationship is for only one evening. If the person accepts the corsage (or flowers in general) it shows that she has agreed to enter into this relationship with you, and that all is well. If she refuses your gift...well, let's not talk of that.
You go to dinner if your prom tickets do not include it. Depending on where you go, dinner for both will range between $50 and $100. It is traditional for the guy to pay for dinner; and if you make your date pay, then you deserve to go dateless... Just kidding!... But it is traditional for the guy to pay. It is also traditional for him to select the restaurant and to make all the arrangements. However, you should check with your date first because, if you make arrangements for a sushi dinner and the very idea of raw fish on rice makes her gag and turn blue, then you have a problem.
Do you need to give your date a gift? No. You don't. Should you? That depends. If you're going as friends, and she knows this, and you know this, and there's no intention at all of hooking up, then you certainly do not give her a gift. If you're already dating, a gift--maybe jewelry--is a good idea. If you sense that you're going to start dating on prom night, or if going to prom together means that you both like each other, then you can, and I encourage you, to give her a gift. What should you give? There's nothing traditional, so that will depend on her character, on what you can afford, and on what sort of message you want to send with the gift.