Regularly on Saturdays there are Bondens marked (Farmers Marked) in Åndalsnes, or in other cities near Åndalsnes. The market hosts traditional food and handicraft product. When in Åndalsnes the farmers market is inside the city hall, or when the weather is in the pedestrian street just down from city hall.
Two very creative ladies who makes a lot of nice handicraft products in a old farmhouse in Innfjorden (about 10-15 minutes out of Åndalsnes).
What to buy: Wool, fabric and woven products. Wool seating plates are very popular.
What to pay: Depends on what you would like, most things are between 50 and 1000 NOK, but some bigger stuff might be more.
I don't know about you, but when I buy souvenirs from a trip I like to get something that is typical for the area. Typical for the area are of course Trolls, but before you buy take a look underneath and check if it is made in Norway or China. A lot of the trolls are mass produced in China, just a tip to those of you that thinks that things like that matters :)
The area around the car park at the top of Trollstigen has a number of stalls selling 'souvenirs', mostly trolls of various shapes and colours. Expensive but tacky, they are not worth a second look. Don't bother with them, admire the view. You'll find nicer things in shops elsewhere.
In the picture one of the tacky trolls put there to encourage prospective buyers. If I were a real troll, I'd do something about that monstrous image of me. Push it down the mountain perhaps?