i use "itrimming.com" on ebay for my screen protectors. Its costs less than 10bucks for about 6 screens covers(front and back). They're not the super top quality but ive had my 4 for quite some time and ive dropped it on gravel twice! and these protectors have save the glass both times. Every time i remove the screen protectors and and clean the glass it looks as good as the day i pulled it out of the box.
or you could spend 10 more dollars and get the zagg.com invisible sheild
5 year warrenty...if it scrathes they send you a new one.FOR 5 YEARS
best twenty bucks for my iphone ever