Well, I'm in eleventh and also going to coaching institute and preparing for it.if you don't wanna join any you may go for online materials like TOPPR as it is cheaper and you can do it using reference books. I would never say of its impossible but I found coaching better as I'm in advanced batch and it's all good here. you should also care about your scores here becoz it decides your batch. higher the Batch higher the attention even there is difference in environment between lover and higher batches. I'm in second batch and all are pretty smart here. but in first batch all are nerds and they never talk. you would find that shocking but there are some people here.NOTE: you will need self practice everywhere wether you are in institute or you do it personally.Best of luck....nowhere to reply so......you can solve MTG subject magzines free online. they are good to solve problems.I dont recall of having heard about FREE books, exept ncert (lol).you can get lectures on YouTube. andUpcoming THE GREAT INDIAN SALE on Amazon is gonna be house to buy all preparing books at hefthy discounts, so overall a good deal

You must solve previous year question which help u understand the concept and u can solve problems by your own then..