> Or is it $4.20 with the comma as decimal separator as seen in some non-English-speaking European counties

Most likely this considering it is a French website.

https://ankuj3.wixsite.com/website-5/cgu

$4.20. Because sometimes Europeans start companies in the US.

And when they charge USD they should learn to correctly format USD-denominated amounts...

You have a point but is there any currency notation in which 4,20 can be equal to 420 - thus omitting the "," ? When for example I see 4.20, as a European I assume "." is the decimal separator and not a mistake thus the number 420

If I have never seen a European decimal comma I would certainly be very confused -- most people aren't familiar with foreign currency notations and a hundred separator assuming that's a thing (most people aren't equipped to answer the question of whether it's a thing, me included) would be as foreign as a decimal comma if not less when you're familiar with comma as a thousand separator.

(I was confused for a second anyway but tipped off by the outrageousness of $420.)

Edit: Since this is Hacker News, let's talk about programming languages. 4_20 is the same as 420 in Python (3.7+) but not 4.20; 4'20 is the same as 420 in C++ (14+) but not 4.20.

If you haven't encountered the other system, you might expect it to be consistent everywhere. Or otherwise you might expect most people to understand either version. I don't think it's a big deal.

Sounds like you were never really in doubt of the answer...

Not that it matters much, but decimal comma is somewhat more widespread than "some non-English speaking European countries": https://en.wikipedia.org/wiki/Decimal_separator#/media/File:...

You could ask them...

Hi guys, the culprit founder here. Indeed 4,20 => 4.20 Apologies for the snafu, been corrected now :)

and pay $4.20 :D

Or $420. Risky.

Just kidding, it's USD 4.20.

In Britain it's normal to separate pounds from pence with a comma, at least in handwriting. In handwriting people also use a dash. A dot just isn't visible enough. If you do use a dot then it should be a proper decimal point (£1·50), not a full stop. Typewriters are the work of the devil.

EDIT: It looks like I'm wrong about the comma used to separate pounds from pence: that's not normal in Britain. (What about '='? I think I've seen that in handwriting, but I can't say for sure in which country.)

Never seen a comma used in Britain, during my almost sixty years as a native. It's usually £1.50 (and yes, a central dot not a period unless typed), occasionally £1-50 which is most commonly seen on shop and handwritten market signs.

Pre decimal was almost always a '-' when there are pounds, a / (more like a super long apostrophe) when under 240p. So £5-2-6 for £5, 2 shillings and sixpence, 7/6 for seven and sixpence. Less common was £5 6s 2d, or slashes £2/19/2 3⁄4d, but there were a lot of conventions for written Lsd, with nary a comma among 'em. :)

Edit: to your edit, = was common (seems much less so now) for whole pounds, and in the pre-decimal era too, e.g. £1/==, or simply £1==. Also pre decimal whole shillings: 5/=, sometimes 5/-. In the days we still wrote cheques when it was for whole pounds it was common to fill the remainder of the figures box with two lines, essentially =====, after the £250 or whatever numerals.

> In Britain it's normal to separate pounds from pence with a comma

I've never seen that.

Ummm, £1.50 is how almost everyone would type it or write it. Commas as decimal separators is most commonly used in mainland Europe I think.