Located in the Covered Market, the Alpha Bar offers the cheapest vegan lunch in central Oxford. The hot vegan meal of the day (usually some type of curry or chilli) to take away is £4.30. The salad bar is good too with lots of vegan salads (e.g., lentils, chick peas, quinoa, butter beans, cous cous, coleslaw, tomato, greens), as well as hummus, falafel, and baked tofu.
As other reviewers have rightly noted, the major downside of the location in the Covered Market the plethora of butchers, fish mongers, and cheese shops. The same food at Alpha Bar, however, can be found at Will's Deli on Woodstock. Additionally, the vegan hot meal can be found at Vaults and Gardens on Catte Street (although it's more expensive and there are less vegan options).
Save on packaging and bring your own take-away container!
Cons: vegan-unfriendly location, long line-ups at lunch time, smelly/gross location