Weddingbee boards

So my guy friend from college who I am no longer close with got married last year with a very small reception of close friends and family only. I was not invited. As a side note, I have not met his wife nor seen him in about 3 years.

This year, his wife's parent's threw them a blowout anniversary party complete with save the dates and beautiful letterpress invitations. I'm thinking this is their real "wedding" now that they (or their parents) could afford the big reception and from the resultant pictures it looks like the bride wore her wedding dress again. So, it's basically a wedding, from the looks of things.

That being said, I did not end up going to this anniversary party/re-wedding (my brother got married a week later and the stress was too much) but I would still like to send a card and a gift to show I care.

The question is, do I give them what I would have given if I had attended the original wedding ($100 or $200 if I brought a date) or is it okay to give a small gift off of the registry or a gift card for $50 from Macy's (the store at which they registered)?  I would feel bad sending an empty card. (I know it's lame and materialistic, but whenever I get a card and it's empty, I get that wave of disappointment, however fleeting, so I don't want to subject someone else to it haha)

I don't want to seem like a cheapskate but I also don't want to give them too much and make them feel uncomfortable or my bank account more empty.  Please help!