My friend has been a good friend for around 2 years now, she has one daughter, I have 2. when the school holidays are on we sometimes arrange to do stuff together which is nice, the problem is she has more money than I do and only one child to pay for so when we're talking cinema, mcdonalds, horseriding etc she doesnt seem to realise that it costs me twice as much as it costs her but when I cancel or say I can't do things due to money I'm sure she thinks I'm just being unsociable. For instance, we were talking about going to a park at the other end of the city next month during the holidays, to get there we need to get 2 buses each way so for her she just has one adult and one child which costs around £1.70 per bus (£6.80 for the whole trip there and back), for me it costs £2.50 per bus which is £10 spent straight away and then the dinner too which costs a fortune. I also have my 2 kids birthdays next month and Im also trying to save for a holiday.
How can I explain to her that although I like us spending time together in the holidays I just can't do it much this year due to other finantial commitments without sounding miserable and dramatic?