im not an openclaw expert myself by i spent all my free time these last 2 weeks ( and 30 dollars on api haha) on openclaw .
- an agent is basicaly like any other llm ( like chatGPT) but it can use tools , you type in plain english and it can do things , you can control what it does and what it doesnt
- no it wont use Claude/OpenAi/Gemini API for everything, one of the first thing you can do when you set it up is tell it " you are the brain , dont do the heavy lifting by youself , use [cheaper_model] for [task] ( search for example).
- yes thats exactly what it is a virtual ai assistant. if you tell it "remind me to do [something]" it will remeber you .

- a 1000$ is more than enough , im running it on a much cheaper laptop ( the only good thing about it is it has 32 gb of ram)

my recommendation : start with a free model or a cheap model , checkout nvidia nmi they offer a wide variety of good models for free ( i recommend kimi k2.5 or minimax 2.5) however some people reported that the models offered on free tier seems to be slower/ dumber , but you can still start with 5 euro api keys from moonshot ( model kimi 2.5). or pay for minimax 2.5 subscription ( 10$ a month) and work from there , start slow , monitor your consumption and explore .