Answer to: How much to repair the left button with a crack?Most shops will charge between $40-$65 for the iPhone 4/4S Screen Repairs. The cheapest repairs around are 99% of the time using a cheaper quality LCD (lower quality screen = lower price). If you plan on keeping that phone for a little while, try to find a shop with a good warranty behind their parts. Good luck in your search!
Answer to: Best glue for attaching screen to phone?There is an adhesive called 'Red Tape' that is very, very good adhesive. We swear by it for any and all adhesive jobs we run into. Just make sure that you get everything right the first time, because separating Red Tape can be a real pain.
Answer to: How to remove sim and micro sd card housing?Hey there, Milin. I hope this helps. Use the iFixit Guide from here to remove your Galaxy S4 Back Housing and Mid-Frame. From here you'll just disconnect the Sim Tab from the motherboard and transfer it over to your new board.