Wow, it's strange the different customs we have for weddings JUST in the US. Being from South Louisiana we have traditions all of our own that I guess some people could misinterpret as "tacky." There really isn't a "normal" amount to spend on a gift, really just whatever that person can give is appreciated. $250 seems a tad excessive for someone you don't really know. Most of our aunts and uncles didn't even spend that much for our wedding gifts. We got more than enough stuff though because we had invited SO many people. (Also, with most people, if they gave a gift at the shower, they didn't give one for the wedding).
Anyway, we also had a money dance where the people who participated gave each about $20. I know you're thinking this is tacky, but it's just a funny tradition in South Louisiana that no one thinks twice about. If you DIDN'T have one, people would be "talking" more about why you didn't.
My point is that, my DH and I weren't really looking at who gave what. We were just happy that everyone was there and thankful for whatever they gave us. OK one person, who apparently doesn't like my dad, didn't attend the wedding and sent a crappy, ugly, small re-gift vase with the original "to and from" tag for SOMEONE ELSE!!!! Why even bother? THAT I noticed! If you don't do something like that, anything you get will be fine.