
You should be able to walk around most of Andorra La Vella. The town is really in two parts. There is the newer section at the North end of the town that is very commerical with lots of shops. The other half is the older half, down across the river and to the South and West. This also has quite a number of shops and places to eat and also the historic part.
If you stay in either of these areas, you can easily cover on foot, but walking from the end of one half to the other will take a good half hour or more, so it is worth taking the local bus which is cheap. Be sure to read the timetable and routes carefully on the bus stop.
The best bargains can be got in electronic goods and jewelry. High cost items tend to be cheaper than anywhere else because of the low tax.
The great thing about the electronic goods like digital cameras is that there are a huge range of shops and a huge stock range, so you really get to see all the different makes and models.
Some of the larger shops seem to stock a lot of brand label clothing.
There are loads of ski gear shops. The best advice is to shop around.