<human>: Give me the gist of the text in a nutshell

My friend is getting married this summer. When she first mentioned to me 6 months ago that I would be invited, I was obviously thrilled and planned to attend, even though it's an out-of-state wedding. We are just fairly good friends, so I was surprised to have been asked. She sent the Save the Dates out three months before the wedding. As with Save the Dates, they just included the date and location. I didn't feel I could book a flight based on this information alone, and expected she'd send the invitations relatively quickly. However, the invitations were only sent this past week - a month before the wedding. At this point, I can no longer afford to attend as the price of flights and hotels is far too high. I spoke with one of my friends (not a mutual friend) and she said that I still had to attend as I could've booked a flight etc based on the Save the Date. If I were to attend, I would be using a rather large chunk of my savings to do so. Is there a polite way to decline the wedding invitation? Could I offer to take her and her husband out to dinner once they are back in town?
<bot>: Friend send wedding invitations out one month before an out-of-state wedding. I can't afford to attend. How do I handle this?