What exactly is wrong with my phone and cost to fix

I dropped my phone and now when I try to turn it on the display is messed up. There are no visible cracks while the phone is off and the phone still works, I still receive calls and texts and can tell the touch screen still works as it should but the when the display is on it shows random colored lines and a large crack. As you can probably tell I don't know much about phones but I assume there is a protective glass screen on the outside which was not damaged and the LCD display underneath is causing the issue. I took it to a phone shop and was quoted $70 for the repair. So is it safe to say the issue is the LCD screen needs to be replaced and if so is this a fair price given the part needed goes for $20 or so on ebay or should I try another shop? I would try to fix myself but need to be in contact with a few people and also don't want to risk losing some of the important information I have saved. I hate spending $70 on a phone worth $50 though.

phone off

when turned on