[atmosx]

You have to provider at least some information (what kind of application, expected traffic, design, what level of HA is required, what's the probable bottleneck, etc.)

[Mister_Y]

You're completely right, the thing is that I'm not sure about that as the amount of people that will land on the page will depend on the success of the marketing/crowdfunding campaign.

Also, the type of application is an easy concept for booking (via online form) vacation experiences, so it has terms and conditions, explanations of our service, cities in which we're offering it and not much more

[dtnewman]

Is this a static website? When you fill out and submit the form, what code do you have that receives and processes said form? You indicated that you built this with CSS and HTML, but those aren't server languages. Is there something else that you are using to process the submitted form? Do you use some third party service to do that? What would be helpful is a technical explanation of what you are trying to do.

[Mister_Y]

Yes I am using php on the server side to update a database when the user send a form

[dtnewman]

OK. You should update the original question you asked to include the fact that the server side code is using PHP and you'll probably get more targeted responses. Also, which database are you using and where is that being hosted?

[Mister_Y]

Thanks, I'm planning on using MySql allocated in the own server as I'm using now in a free hosting server

[atmosx]

I would use AWS, EC2 + RDS for now. A t2.micro should get you started. Make sure you automate the installation using Ansible (it's slow but you don't care, most importantly it's easy to pick-up and it's relatively agentless).

At this point, that's it IMHO. I wouldn't even use an ELB or auto-scaling at this point.

If you need help, drop a mail, I have spare time I can help you with the specifics (free of charge ofc).

ps. AWS has a learning curve and is not cheap but saves you a great deal of sysadmin management and most importantly, saves you from probable fire-fighting at this stage, plus there is the free tier will get you nearly a year without charges.