Renting a few computers to do remote rendering is not a bad idea. This can help you to work normally on a personal machine while still in control of the rendering process. Here is some information that I think will be necessary for you if you want to use a remote machine rental service.
You get access to significant hardware resources. When you create an account with a cloud provider, you get access to a large number of servers in a lot of configurations (virtual or bare-metal, depending on the provider).
You pay a lower hourly cost, compared to an online farm. This is because you are basically renting infrastructure and not a rendering service. You have to know how to make that infrastructure work for you, but if you do, you can shave a percentage of the total cost of rendering.
Paid solution. All that infrastructure comes at a cost. Depending on each cloud provider’s policy, you can rent machines by the hour or monthly. Prices start low for small machines (1 core CPU) and go up as the hardware gets better. You also need to pay attention to the definition of a ‘core’, as it may vary from provider to provider.
You need significant tech skills to make it work. It’s true, you can get access to all that hardware, but you have to make it work in the way you need it. And this goes beyond just installing the operating system and 3D software – you need to know how to build an image and distribute it to all the machines, how to use the machines together, how to protect them from being accessed by a 3rd party, and so on. Also, in most cases, you need to do a bit of programming as well – think DevOps.
You need a good understanding of the cloud concept to get optimal results. While all cloud platforms offer similar services, each one has its own peculiarities. Access to machines can be limited, the pricing scheme is more complicated – you get billed separately for the machines, for the storage, for the bandwidth, and in some cases for the IP addresses. Also, you need to determine which machine has the best price-performance ratio, and do this on a periodical basis, as prices change. Plus, some of the cloud resources may be volatile by nature.
The time investment can be significant. Even having all the knowledge, you have to invest quite some time. The initial setup is always a bit tricky, and documentation for cloud usage can be unfriendly at times. Also, if something goes south, you need to take the time to understand what caused it before you start fixing it.