New army wife

So my husband starts basic training on May 9,2021. He will be going to basic training in the same town we currently live in. At what point am I able to go on base and get an ID card for myself that way I am able to buy groceries at the commissary? He will graduate basic training and will have a couple of weeks until he has to report to Fort Sam Houston for AIT for 47 weeks. Is housing on that base fairly good? Or should we venture out off post? Also, our daughter will also need to go to daycare, roughly how much does that cost?