Hello Johnny, sorry to hear about your problem. Considering you have the lines on the screen that you are talking about, i do not think it is an IC chip problem. I would just go ahead and do a LCD and Digitizer replacement for the phone. If you do it your self or take it to someone to fix it, you can test the new screen before actually installing it, and that will tell you exactly if it is the IC chip or not. since your trying to get it done for as cheap as possible, doing it yourself will save you some money, although i do not really recommend it. First make sure it is a 6s plus. On the back of the phone on the bottom it will have a small "s" under the "iPhone" letters. If it does not have an "s", it is just a regular iphone 6 plus. Which is good news because the LCDs for iphone 6 plus are way cheaper then iphone 6s plus (yes the 2 LCD's are different, its so stupid). When you buy the LCD, make sure they have a good return policy as well, just in case your IC chip is damaged, you can return the screen and not lose any money. I would suggest just ordering it from amazon. and dont try to buy the cheapest one, sometimes they are faulty or not compatible.
If you have any more questions, i would be more than happy. Just make sure you verify exactly which phone you have, then even if you are going to take it somewhere to get fixed, buy your own screen and just have them charge you for labor. Its much cheaper that way.