Batteries are what will power all of your electronics. By default they'll power anything 12v (lights, water pump, etc...) and with an inverter, they'll power 120v (laptops, microwave, A/C). The goal with solar and generators is typically just to keep your batteries charged, and the batteries will provide the power.
You'll most-likely need a 12V deep cycle battery. A standard car battery is different, so be sure it's a deep cycle battery.
Every electronic you have draws a certain amount of amps. A laptop uses 2-4 amps all the way up to a microwave at closer to 100 amps. Multiply that by how many hours that electronic is drawing power and you have amp hours, which batteries are rated in. You can use this calculator to determine your needs. Most people go with 200-400 amp hours, but you can get by with just 100
Keep in mind that if you're going with lead acid batteries, you should only drain your battery down to 50%, so you'll typically needs to get double the amount of amp hours you think you can use.
Typically you'll buy multiple 100Ah batteries and combine them in parallel to get 200, 300, etc... amp hours
Lithium batteries are by far the most expensive, but also much better than lead acid and AGM batteries. They can be discharged more without damaging the batteries, charged quicker, are lighter-weight, have longer lifespans (more cycles), and have several other benefits. Since it can be discharged more, a 100Ah lithium battery is roughly equivalent to two 100Ah lead acid or AGM AGM is the middle ground - they don't require venting or maintainence and are priced between Lithium and AGM Lead acid batteries will be cheapest, and they'll definitely work, but they do need to be vented (most RVs have a vented spot for batteries) and typically have some upkeep (checking / adding distilled water every few weeks)
Basically any battery you get is going to come from China. With Lithium batteries, most cells (battery internals) come from China, and with some, they're assembed in China vs others assembled in the US. The "Name Brand" will get you a better warranty and support, but will cost more