@ReversingSnail
Throw a post-wedding party for your friends when you get home instead?
The OP isn't going to do this. She isn't going to spend money on others. 
She says she has no money to spend on folk, but is managing to have her wedding in Spain. 
As she wants to invite people 'at their own cost,' she should go ahead, but don't expect barely anyone to go. I wouldn't.
I have a deep rooted loathing for people who get married abroad, especially when they are BOTH British. I mean, WTF? WHY? What are they trying to prove? 
They can't be to bothered about people going, or they wouldn't have it abroad... I would hate to treat the people close to me like this. 'Yeah come to my wedding, but it's in SPAIN, and you have pay for the whole trip yourself. For you AND your family.' 
And don't anyone call me 'narrow-minded' (like someone said earlier in the thread.) It's not narrow minded to not want to spend a 1.5 to 2 grand, on going to someone's wedding 1000's of miles away.
My friend's cousin had his wedding in Cuba - fucking CUBA! It was going to cost people around 2 grand per person for the trip. Unsurprisingly, the only ones who went were his parents and her parents, and the bride and groom, And HER little sister who was a 'flower girl.' SEVEN people at their wedding. I have more people at a Sunday afternoon barbecue in the summer every other week!
What a miserable, shit wedding that must have been. I reckon I'd have more fun at a fucking funeral.