Somebody proudly tells me they got hosting for 3.99 a month. Then asks why the site is slow. Those two facts are the same fact.
What you actually bought
A slice of a machine you are sharing with somewhere between five hundred and several thousand other websites.
When one of them gets a traffic spike, your site slows down. When one of them gets hacked and starts sending spam, the whole server IP can get flagged and now your contact form emails go to junk. You did nothing. You just have neighbors.
That is not a scam, to be clear. It is exactly what four dollars buys, honestly. It is just not what most people think they are buying.
Why it caps everything else
Server response time is the delay before the browser gets the first byte back. Nothing you do on the front end happens before that.
So if your server takes 1.2 seconds to think, your best possible load time starts at 1.2 seconds. You can optimize every image and delete every plugin and you are still standing on that floor.
That is why I say fix images first and hosting second. Images are usually the bigger number. Hosting is the ceiling on how good the result can get.
What to ask before you buy
What PHP version do you run. If the answer is old, everything else about the operation is probably old too. This one question is a surprisingly good proxy for the whole company.
Are backups included, off site, and how far back do they go.
Is there a staging environment. If updating a plugin means updating it live on the real site, you are going to break something in front of a customer eventually.
And who do I talk to at 9pm on a Saturday. Sometimes the answer is a chat bot and a forum.
What it should cost
For a normal small business site, somewhere in the twenty to forty a month range gets you real resources and real support. Under ten is shared and you are gambling. Over a hundred is usually more than a five page site needs.
Care plans include it, which I think is the right way to do it. One person owns the hosting, the updates, and the site, so when something goes wrong there is nobody to point at.
You are saving fifteen dollars a month on the foundation of the whole thing. It is the wrong place to economize.