hi there tomatoSoup,
any tank smaller than 2ft tank is consider small for parrot fish. i think to fit a pair of parrot fish in a 2ft tank is just reasonably fine. but think again twice, in future, if you would to add more parrot fish or other cichlid into the 2ft tank, i think they will get more stress due to less of space to swim around, some may ended up have torn fins fighting each other for territory (may end up dying).
i think most of the aquarium shops we can see near our homes will have cheaper price than the ones they are selling in shopping malls. if you happen to go around kepong, there are a few shops i have come across that sells just the 2ft tank (without the steel legs that supports like a table stand) is about RM50+/-.