I have a mortgage, kids, car and a divorce behind me, still went to Lewis and Uist this year. Hopefully I'll be going to some Scottish Island next year too.

Things that help keep prices down are....

Sleep in a tent, or the car.
Eat crap from garages.
Drive economically.
Stay away from tea rooms.
You don't need to stay all week, a few days will do.

Easy.

The Road Equivalent Tarrif has made a huge difference to many of us. It started off with a pilot scheme in 2009 I think and by the end of 2011 RET was bestowed upon all routes to The Western Isles plus Coll and Tiree. Islay, Colonsay and Gigha followed suit the following year. I still do an Arran jaunt every Summer. A few years back that would cost around £150 for myself, my OH, my young son and a wee hatchback. Now with RET being thrust upon Arran a couple of years back, the cost is less than £50.
For the likes of us, that saving of £100 can then be invested as a gratis contribution towards one's self-catering accommodation, or as we like to do, spend it on big steak dinners, plastic flip-flops and ice creams.
RET has rendered island hopping to about a third of its price of ten years ago. That's the stuff. Better than politicians spending it on cocaine, duck-houses, prozzies and rent-boys.