Munaka, I really don't know about how they afford the weddings...really, it's none of my business. I wouldn't ask a friend how they afforded their wedding either, if they didn't volunteer the information.
However, bear in mind that Traveller's acquire few possessions in a lifetime and all their wealth is on show...that's part of the culture. It used to be gold that was the mark of wealth...the more gold a woman wore, the more successful her husband obviously was. It was easy to carry & takes up little space...important when living in cramped condtions; pawnable if necessary. You don't see that so much any more so I guess cars and expensive weddings are the mark of your success.
Weddings are also a bit like a dowry. Most Traveller marriages are arranged to some extent so it's the bride's father's 'proof' that his family is worthy of marrying into the groom's family if he can put on a lavish wedding.