There are guys out there who make more without a website rather with a website so Yes , you can do it too
Yes. How? Via working at freelance site. How much you have to pay to start working at freelance site? Nothing, at many freelance sites, its free to start.
There is no one singular answer to this. It all depends on what you are selling. If you are doing web hosting, web design or selling your web scripts, you should have a web site to showcase your items. However, if you are offering dog walking services, offering babysitting services or accounting services then there is no need for a website. Technically speaking, if your products and services are tailored towards web users or international customers then a web presence is needed. If you are offering local services then you do not need one. I would supposed even if you just use eBay or forums to post your offerings, it is somehow some web presence. A website would show your professionalism and at least to me, it shows that you are here to stay and not just an overnight business. Domain names and web hosting are extremely cheap these days so it is definitely a good idea to have one if you are serious about your business.