If you are at a fixed location long term and you do not have access to DSL or similar you can get satellite internet service but it's not really from Dish or DirecTV. They resell services from other vendors such as Wild Blue, Excede and Hughes.
If you want a mobile satellite internet service you can forget about Wild Blue and Excede as those services are spot beamed and cannot be relocated by us RVers. Hughesnet service is mobile, however, not the new Gen4 service. You must get "someone" to sell your the old HN7000S modem and the appropriate "very large" satellite internet antenna and tripod setup. New they are around $1200 but many are available used for a few hundred dollars. The other mobile satellite internet service is sold by Starband but their are many less users and help is hard to find.
Understand that consumer satellite internet like I am discussing is quite slow and suffers from high latency (delay) caused by the signal having to make 4 22,300 mile round trips to send the info and have it return to you. Average upload speeds are only about 100-150K (.1-.15MB) and download speeds around 1MB. Monthly service charges start around $60 but may cost as much as $80 for the service speeds listed above.