So : ) I stayed in Pelana a bit out of Weligama the town right on the beach. Cities in Sri Lanka are usually noisy, crowded, full of markets and folks selling various stuff on every step (except some tourist only areas in Colombo, Galle fort etc.) So I wouldn’t recommend staying in town, and also close to main roads / railways – it’s a pain. There’s traffic all the time during the day.
I do not recommend booking through the internet as prices are 5 - 10 times higher than if you hit the road and haggle with the hosts. I got my place for like 100 000 LKR for the month which I consider super expensive for Sri Lanka. But location was good for me, it was right on the beach and the host was a very nice guy : ) But I’ve seen decent options for about 2000 LKR for night (for a monthly rent).
Restaurants were good at nearby resorts, also in Weligama there were couple of European options. I mean like in every place where there are some tourists you can find a nice restaurant / bar. They are not expensive, even the most high end rarely charge more than 10$ pp. If you go to where locals go you can get stuffed for like 3$. Given you can eat very spicy rice and curry
There was a market in Weligama and a supermarket. Folks at the market name different prices for locals and tourists (there were no prices listed :)), so it was often cheaper to buy stuff at the supermarket (Cargills Food City). We travelled a lot by buses: very cheap, run often during the day. But you will be offered a tuk tuk on every corner
Internet: I experienced good 3g coverage on dialog throughout the country, upload speeds were bad though at Weligama (< 1 Mbps up, 3 Mbps down). It’s better in the cities. If you rent a place verify that they have WiFi they claim they do Dialog has very limited 4g offering on band 3 now in major cities (make sure you get 4g capable sim card), but it also has a fixed LTE network available for locals, so it would be good option to rent a place that has the router for it).
Now, the bad part were power outages. They were not super frequent, maybe 3 a week for 1 - 2 hours and cell towers were working, so it was not as bad as it might have been.
Hope that clarifies stuff a bit, let me know if any questions.