There are other options than paying $20 for every game - I believe the Bulgaria game was included in the annual Setanta online subscription package. Also, if you have any friends or family in Ireland check out
www.slingmedia.com - I can watch RTE, BBC, ITV and Setanta Ireland over the interweb at no cost beyond the price of the Slingbox.
As for the away trips, I currently live in New York and booked a flight to Sofia for next month's match for less than some of my pals are paying from Dublin. It's not cheap by any means but even from New York it is possible to attend a lot of games with a few financial sacrifices elsewhere.