cheap tires are cheap tires, if its just price youre going on, youre not going to get anything very good. If youre looking for an ultra high performance summer, in the 90-125 range, stick with 225/50r16 and grab the bridgestone re01r's. They wont last long but theyre super sticky and will hold better than any cheap 245/50r16.
From both experience and research, going wider than 225 on a 7" wheel is just bulging the tire and making extra roll in turns. Im gonna burn up the 245's i have on the back of my car as quick as i can so i can have an excuse to either go back to the right size or get bigger wheels.
Also, the bridgestone potenza re750 sport is bridgestones latest ultra high performance summer tire and its supposed to be one of the better wearing uhp tires out there at a very reasonable price.I put them on a customers car recently (245/40r18) and he RAVED about the grip. I can guarantee better results out of a better 225 than a cheap 245. not to mention since 225/50r16 is a more common size than 245/40, the 225's will have more to offer and be better tires for the buck. Just .02 from someone who sells tires for a living. hope it helps. PM me if youd like further advice or info.