I will be traveling for a few weeks in Scotland in June and was wondering if anybody can tell me the cheapest, best train tickets to buy with flexibility? I had the Britrail pass once before, but looks like it is very expensive these days. I will travel from London via train to Edinburgh, then Edinburgh to Inverness then drop down from Inverness to Glasgow and will rent a car there for the rest of the trip in Ayr. I will need to get back to London at the end of the journey to fly home unless I can fly out of Glasgow. I love the train travel, but don't want to spend a fortune. Thanks!!!!

Point-to-point tickets will be cheaper than a pass IF you can commit to booking them in advance. For example, booked well in advance, you can take a day train from London to Edinburgh for around 15 GBP. The Caledonian Sleeper overnight service from London to Edinburgh has "bargain berths," but they're already gone for your travel dates. Still, even if you have to pay regular fare, it's a good way to cover ground and save the cost of a night in a hotel.

Flexibility, whether it's "last minute" p-to-p tickets or a railpass, will cost you. Go to www.nationalrail.co.uk for timetables and fares. Then compare what you find there to the cost of a railpass.

Besides London > Edinburgh, if your only other train trips are Edinburgh/Inverness and I'ness/Glasgow - there probably isn't any sort of pass that makes sense.

As TimS says, point-to-point will be much cheaper if you book well ahead. But even walk-up fares will probably be a little cheaper than a pass.

Why do you need to rent a car in Glasgow to get to Ayr? Just book your ticket from Inverness straight through to Ayr. It involves a change of station in Glasgow (Queen St to Central)and the trip to Ayr is just under an hour.
From Glasgow you can fly to New York with Continental,Philadelphia with US Airways or Boston with FlyGlobespan