So theres this new promo, if i upgrade new phone for free and then get a 100$ gift card. Also i have paid my tab and i have 62$ tab balance. Can i use them both and buy my son a nexus 5(200 with a tab small) then minus 162? is it possible?
Just make sure that the gift card deal isn't for new activations only and that it is indeed for upgrades for present customers.
Oh and actually now that I read your question againiit looks like you want to use your tab to purchase a phone for your sons line which if you hats the case it can not be done as tabs are non transferable and can only be used on the line they are for not other lines on the account or other accounts Unfourtunatley.