I'm still bitter about not getting selected for the 1995 one.
Two days of selection all based on points me and my mate were near the top until lunch on the second day and then ended up outside of the number needed to be selected, all those were selected from just 2 out of the 7 districts in the county, all those selected were also known before hand by the selection team.
It will be a great experience, it may be worth looking for local grants and trusts, the lions, rotary, and round table to see if they can offer assistance.
As for the cost most of it is down to the cost of flights iirc something like £1400 for the flights.
The cost is worked out so that richer countries subsidize poorer one's, in the UK we are in the top bracket.