Bridesmaids dresses can be expensive, and often are not worn multiple times, which is silly considering how expensive and nice* they are. Luckily, groomsmen don't get those. However, groomsmen attire can still be very fancy, expensive, and ridiculous. Having been a groomsman 5 times and married just once, I can relate.
The key with groomsmen clothing is twofold: 1 make sure whatever you get is approved by your future spouse, and 2 make sure that what you get can be worn again.
1- This item should seem pretty straight forward, why wear something that your spouse would not like? So get that approval first when looking at what clothing you are going to have don along with your 1-12** closest friends. Now this item may seem straightforward, but for saving money it is not. There should never be any reason that the groom has to buy a bunch of shirts to see how they fit and look - just go to the store together or the internet and decide together. No one should be doing this charade more than one time. Save money and time by making sure you don't make a wrong decision, and by letting the real decision maker help you make the right call (hint for all you future grooms out there). Side note - for all guys who are really into fashion, cool, just still listen to your spouse unless you are told otherwise.
2 - This one is not as easy. People live all kinds of varied lives with different types of work and social structures. Some might need to dress fancy on a weekly occasion, some might do it once a year. Try to make sure that any shirts, pants, and accessories be useful to those people. That means if you are given the latitude to pick shirts and patterns, please don't make them stupid or ridiculous. For instance, I have a shirt from a wedding that is so bad I refuse to wear it at work (and my sense of style is terrible per my wife).
Weddings don't need to be expensive, though some families will hop on that train the instant a wedding is announced. Wedding attire is one of the many things people blow money on, where there is no need to. Renting suits? Don't, buy one - it will pay you back after wearing it 2 or 3 times instead of renting more crap later. Got a nice shirt? - great they likely will be able to use it at work or social functions after. If people are going to pay a lump of cash to be in your wedding party, the least that you can do is make sure their wedding attire is not full of single use items.
Final note - if people are expected to spend more than $150, stuff better be useful...
* well they can be really weird too, I am going off my wife's judgments here.
** for the record I have never seen more than 8 groomsmen, but I have seen 12 bridesmaids...
Do you suit up all the time or just when you have to? I only do it when I have to.