wifi where?

You ask "other than hotspot on phone" so I presume you don't have that option. I recommend googling the security of different public wifi spots. I think a phone hotspot is more secure than most public wifi. I most definitely would not use a Starbucks or McD's to pay bills. I've paid bills on campground wifi before. Another issue to research is spoofing public wifi. Sad we have to think about such things but people will set up a router and call it Starbucks, Boston Logan, etc. and it will connect you to the internet for free. The catch is they monitor all traffic in between and can steal passwords and you will never know it until they use the info (likely sell it to third party.) In an airport, it's a little easier because it is probably done with some type hotspot which if you know what to look for has a different symbol (two links of a chain) than wifi. But at a Starbucks, it could be placed in a building next door and look the same.

Not trying to scare you - just a little primer for you to do your own research. You're profile is TX. At least some rest areas have wifi. I would trust that before a restaurant. Less likely to get intercepted.