Another option to consider is an LLC (Limited Liability Company) essentially a US version of Ltd.
The State of Delaware is one the best and lower in cost. Complete registration including agent will cost about $400.00 USD. This is a one time fee. International will be slightly higher but with the Euro or GBP vs. the USD, this may be quite a bargain.
Annual state taxes are $200.00 USD
All of this, of course, would be tax deductible for you.
Look for firms that include an agent and the agent fees in your start up costs. Also look for firms that guarantee agent fees not to increase.
I used
http://www.delawareinc.com. Total package cost was $374.00 USD which included agent. Follow this link for international filing
https://www.delawareinc.com/ourservices/index.cfm#int.
Been very happy with them for service. Agent fees are set at $50.00 USD annually. This is one of the lowest in the industry.
Many advertisement online charge much less in cost but provide much less in services, no agent, and numerous add ons once you check out.
You will receive a reminder from this company to pay your annual taxes and they will be glad to pay them for you. But, they will charge a fee. Go directly to the State of Delaware's site and pay them yourself, online, and no added fees.
Just something to consider. I do not own stock in nor am I part of DelawareInc.com but have found them to be to my liking.