I like task management tool GQueues (http://www.gqueues.com/). But the pro version is as costly as $25/mo which is too expensive for me as a student. What's a good replacement to it? I mainly would like its Google calendar integration and reminder via txt messages/emails.
First thing, you got the pricing wrong. GQueues Pro is available for $25 / year. So I think you can afford it easily.
I have tried GQueues and apart from its Google calendar integration I found it lacking in quite some aspects. If you are seriously considering other options, then Toodledo is one of the best task management websites present out there. Their UI is a bit quirky, but once you get the hang of it it's really useful. If you are following GTD by any chance then Toodledo will be perfect.
And Toodledo is also priced a bit lower than GQueues, with a Pro version for $14.95 and a Pro Plus versions for $29.95.
I think I have done enough advertisement for Toodledo. The rest is for you to decide. :)