Do you buy presents for showers and weddings or just 1?

First, congratulations to your friend's wedding and to you. I guess its not necessary for you to buy gifts that are too expensive. What is important is the thought. If you are on a very tight budget and can't afford to buy a gift, I guess your presence is more important. When I attend weddings, i do buy gifts but not necessarily expensive ones. Its the thought that matters and your presence in that special occasion is more important.

Typically you should give a gift for each event - so one for the shower and one for the wedding. However, I think it's important to give what you can afford as a gift and not worry about matching up to "the price of dinner" rule (which I personally think is a silly rule - if the couple wants to spend a lot on their wedding, you as a guest should not have to spend any more on your gift. Your gift should be determined by your relationship with the couple - not their taste in the wedding). You are already commiting a lot of cash to the wedding (with parties, showers, the wedding party, flights, etc.). It would be nice to give a gift at both events, but keep it to something you can afford with current budget. So it might just be a small gift for both the shower and the wedding. And it doesn't have to be cash. While that's what they prefer (as shown by the "fill our bank account" notion), as a guest you have final say over what you want to get them. And if she's a good friend, she should be happy with whatever you are able to give.