Stratford has two shopping centres. Stratford Centre is the older one, which is mainly filled with 'cheapo' shops (Poundland, Greggs, etc) but it also has some market stall-style vendors, so it might be worth looking there for some bargains.
http://www.stratfordshopping.co.uk/
Westfield Centre is very much more modern and 'upmarket'
http://uk.westfield.com/stratfordcity/
Apart from shopping, there's not a lot to do in Stratford itself but (as has been indicated above) it's a good starting point to get into central London or for accessing the Docklands Light Railway. The Museum of London Docklands (close to West India Quay station) is well worth a visit. (Allow a couple of hours. Admission is free but donations are invited).
http://www.museumoflondon.org.uk/docklands/
It's conveniently close to one of J D Wetherspoon's 'classiest' pubs:
http://www.jdwetherspoon.co.uk/home/pubs/the-ledger-building
A trip across the Thames by cable car can be interesting. Either end is easily reached from Stratford:
http://www.tfl.gov.uk/modalpages/23863.aspx
That combines well with a visit to The Crystal (which I really enjoyed):
http://www.thecrystal.org/index.html
Stratford is also just two stops on the Central Line from Bethnal Green, where you'll find the V&A's Museum of Childhood, with free admission:
http://www.jdwetherspoon.co.uk/home/pubs/the-ledger-building