West Kilbride will be the cheapest as Ayrshire is generally cheaper than the rest of Scotland. It is a fair trade village with a few indy shops. Seamill is the nicest bit of town and there are views to Arran.
Arran is also an option or Rothesay or Millport if you can tolerate the ferry.
Gourock is nice, lots of shops. Amazing views. Easy access to Argyll via the ferry. It even has a Lido!
Wigtown, the book town is unique but a bit out of the way.
Moffat is just off the M74 so easy for car access but not sure about the train.
Biggar is also a pretty country village. But maybe too remote?
South Queensferry has spectacular views of the 3 bridges over the Forth, an artist's dream! It has one of the prettiest high streets in Scotland. Plenty of good cafes and great ice cream. Lots of boat trips.
Or across the Forth the East Neuk towns are lovely, picturesque and have makars.
St Andrews is probably too pricey but a great art scene/ theatre/ cinema/ shops/ cafes if you think the architecture and beaches make up for all the American accents!
Pitlochry has a big theatre. Beautiful landscapes all around. On the Trainline. Cafes etc.
Gairloch has a lot for a small village as it's the hub of the area. Access to scenery. But takes a long drive back to the central belt.
Golspie/ Dornoch/ Black Isle (not an island) for the bill other than being much further north. Dolphins. Stunning beaches. Indy shops.
Or the towns in Royal Deeside. Not very accessible but pretty and a mix of access to mountains and big sand dune beaches. Lots of nice shops.