Here's a crash course in Website and Mobile App Hosting - from someone who's owned and operated one of the top 500 most visited websites in the world and countless mobile apps.

First and foremost, before we jump into cost, let's address a few basics.

The jist of this whole reading is that almost everyone can just start out with basic, cheap GoDaddy Hosting with an SSL. If anyone is talking you into anything else, they're full of it or they just don't actually know their stuff as good as they THINK they do. And I'd ask them - have you ever run anything with over 1M users a day? Because if they haven't, then they really don't have a practical frame of reference about how things start and then end up when you grow.

1) Almost Any Hosting Will Do - Most websites and mobile apps can be hosted on just about ANY typical, cheap hosting. If they can't then someone did something in a very NOT industry-standard way and you're going to pretty much be at their mercy. We host most clients right on GoDaddy.

2) There's a place and time for everything. Most projects start off in a much slower way than the client hopes, expects or anticipates. The big reason why is it takes time to really, truly evolve a product (whether that product is a website, web app or mobile app) into a well-oiled operation. There will be inevitable discovery, getting your Users acclimated and tweaks based on all this new information. So if you go and get a $500/mo server right out the gates then it's going to be over-kill and you won't get a return as quick as you think and it's just going to put pressure on you unless you can afford to throw $500+ per month away?

This leads me to Amazon AWS. It's awesome and yeah, a lot of famous companies use it, but it's over-kill unless you have hundreds of thousands of users and/or are very media/file rich (ie. think Dropbox). Because AWS is widely adopted by the Tech community, it becomes a sort of must-have for most new product (ie. website/mobile app) owners. It's really a big misconception and it's appeal gives people a false sense of security which makes them not even do the common sense things that need to be done to ensure realistic up-time and redundancy. If you'd been there before, you'd know exactly what I'm talking about. Have a website or app that has millions of users then have your whole server system go down 1 time and you'll learn real quick what to do to prevent it or rather minimize the effects (ie. damage control). 

Here are a couple of articles to chew on:

https://www.usatoday.com/story/tech/news/2017/02/28/amazons-cloud-service-goes-down-sites-scramble/98530914/

http://nymag.com/selectall/2018/03/when-amazon-web-services-goes-down-so-does-a-lot-of-the-web.html

Lesson: EVERYTHING eventually goes down. Everything. Look up DDOS attacks for starters.

3) Hosting is all about "serving" your website and/or mobile app to end users. The awesome thing about mobile apps is - if they are built correctly, then the heaviest parts of your UI/UX in terms of file size will actually be "packaged" locally IN the app code and downloaded to the end user's phone when they download the app. That means, the only things coming from an actual server are really dynamic (ie. database-driven) text, which is VERY light. So basically you can serve an App to A LOT of end users with just basic website hosting before you need to upgrade.

4) Yes, you should have an SSL at the very least and an EVSSL if you really store valuable, personal data for your users. These can range from $59 to $200 per year.

5) Hosting all comes down to how many users you're serving to. Specifically how many DAUs you have (ie. daily active users) and really you need to take that average into account in a way where you understand how many users are using our resources at the EXACT SAME time? If you have 100 DAUs then you definitely don't need any fancy hosting. Heck I think we had about 1M hits/day and only about 1k to 2k users would ever be online at the exact same time.

6) Server Load, Load Balancing, Hosting vs VPSs vs Dedicated Servers, SSD HDs vs CPUs and Multi-Core. These are all things you'll eventually need to know once you start peaking out the resources of your current "hosting" which is usually pretty easy to see in any typical Control Panel or WHM. And that's really the biggest indicator of how much hosting power you need. Start small, then observe, then ramp up accordingly. Cloud based hosting has advantages because you can ramp us resources very smoothly, but even Cloud-based can be expensive.

7) Cost - So we always advise people to start with a low-cost, fixed-cost hosting, like GoDaddy (whose Delux and Ultimate plans actually have resource upgrades, which make the hosting more powerful in terms of how much throughput they have). With the upgrades and backups, the top plan usually runs about $29/month to month. And if you pre-pay for a year, you'll get a discount of almost 50%.

CLOSING SUMMARY

Once you do get into VPSs, Cloud-based, Dedicated Servers, etc. they all have their pros and cons, but the prices jump dramatically, so you need to be prepared and sure that it's time to do that. Decent VPSs can probably start around $60/mo on average (decent, the thing to watch out for is how much CPU processing you get). And then it all goes up from there. Some people will create a cluster of multi-core dedicated servers (ie boxes) to have the ultimate control, stability and reliability. I believe Facebook uses this approach - and they actually build their own server boxes if memory serves me correct.