My fender Squier guitar's bridge is coming off from one side. How much does it cost to get it reglued? 

Hello Lalit!
It will not cost you much to get it reglued. Just take it to any instrument repair shop, and they will gladly help you. After it's done, you'll need to set up the guitar so that it sounds in perfect intonation. And don't let your Guitar anywhere too much heat... Because Guitar is only wood and glue. Heat hurts it. It may happen again if you don't take care of this.
Thanks!

This is one such problem wherein you can't do anything abt it except purchasing a new guitar.

It cannot be reglued.
This problem arises mostly when you don't loosen up the strings with the help of tuning keys once you're done with your practice and by not loosing up the strings, there is a constant pressure that comes on the bridge....and worst is when you play chuck pattern. More pressure.
(Only if you know what chucking means).
So remember that in future, to avoid this problem, make sure that you off-tune your guitar once you're done with your practice by loosening up the tuning keys,
as no guitar, a technician can help you regarding such problems, neither it can be reglued.
Or else even if you purchase up a new guitar & don't loosen up the strings, it may again give you the same problem.
Hope you're satisfied with the answer and will take necessary precautions henceforth. 😊
Keep practising & keep smiling. 😊

Is it really coming off or Just lifted which we refer as floating bridge ????? Please reply anyways i have a thought about it will share now ok,,,,

Just tighten the screws holding the spring claw a turn, re tune, and if it comes up, give the screws another crank, re-tune, ect.,. until you get it down on the body. Very easy fix 
You may need to check your neck relief and have to tighten the truss rod a tad, and then set action and intonation.