How do i get free apps for my touch screen phone?

My husband and I just got the ATT LG touch screen phones from walmart and they are the go phones where they charge u by the day...we get unlimited talk and text but not web and i was wondering how we can get apps because their is a spot for apps but when u click on it, it wants to charge you for connecting to the web and someone told me i could download apps to my phone from my pc just with my hone number and i was wanting to know where i could do that at and if its free and safe. If this doesn't work then i will add more money to my phone so i can buy them or get the monthly plan so i can have unlimited web access.