We usually drink water when eating out also because drink prices are ridiculous, but some places offer Sr drinks which maybe smaller but if refills are available it’s no big deal. Whataburger offers them and they are free. They charge for a kids drink and ten give a discount for the same amount. They say it can't be done with a combo but we found one lady who knew how to do it, but no big deal as we usually just get a burger any way... Less than $10 for the two of us