You should start with the smallest web space that you can get to test the waters, just incase niche website Internet marketing does not work out for you. You may want to add on later, so make sure that your provider offers that option.
You will want to choose a provider that has a reliable service. If your site is down or takes to long to open up when visitors are trying to get in, it may lead them to click out of your site and move on to the next one. They will also more than likely not visit in the future since they will remember their bad experience. For this reason, it is probably best to stick with a well known company who you can check reliable references on. There are many small hosting providers that offer space for as low as $.50 to $1 per month, however, you never know what you will be getting and many of them want you to pay for at least a years worth in advance.
You will also want one that has the most affordable hosting. If you can create your own small site or have one made for you, then you will probably be able to find space for as low as $3 to $4 per month. However, if you need to choose a company that offers a What You See Is What You Get (WYSIWYG) website builder, then you will probably end up paying $10 to $15 per month for the smallest amount of space. But if this is the only way that you can build a site, then it is necessary.
Some web hosting providers may also offer a deal on a yearly URL or other products when you make a web hosting purchase.
Ultimately, whatever web hosting provider you choose will depend on your individual needs and what you can afford. Hopefully you will be able to snap up a well known provider at a low price who will allow you to upgrade your service as needed.