Here is the honest version, no thumb on the scale. The cheapest sticker is a DIY hosted builder — call it $9–$40 a month on annual billing, more once you add apps and a business email, which is roughly $350–$1,500 over three years plus a $10–$20 yearly domain renewal. You build it, you maintain it, and you never own the platform. For a brand-new one-person operation, that can be the right call. Say so.
The most expensive over three years is almost always an agency build carrying a monthly retainer, or a large enterprise build: $20,000–$100,000 or more to start, then ongoing on top. Running a professional site alone is $1,000–$17,500 a year (OneLittleWeb), before any retainer. That is how a project quietly becomes a six-figure line over three years.
An owned, no-retainer build sits in between on day one and often comes out ahead by year three. From $6,000 you own the code and the domain; static hosting runs low, often under $20 a month; and there is no mandatory retainer draining the account. Three years in, you have paid once and you still own the site. That is the whole idea: not the cheapest sticker, the cheapest thing to keep.