It doesn't really matter if you use cheap shoes or expensive shoes if your running form is bad, you will get hurt.
Generally cheap shoes have less cushioning thus they cannot hide poor form as well.
Want a good example, do a 3 or 5 mile run in Chuck Taylors, if your form sucks, you won't get far.
Your goal needs to be to prefect your form, then it won't really matter if you use cheap or expensive shoes.
You can do this everyday, in fact I suggest you do.
Read this -
http://hundredup.com/learn-georges-100-up-running-exercise/
Watch this -
http://www.chrismcdougall.com/blog/2011/11/100-up-in-action/
Remember, perfection of form is much more important than numbers.