Currency
The dollar sign types itself, but the pound, yen, euro and cent signs all need either an Alt code or their Unicode value. Unicode reserves an entire block for currency, U+20A0 through U+20BF, covering approximately thirty world currency signs, from the historical French franc and lira signs to the Bitcoin sign added in Unicode 10.
Only a handful of these have a genuine Windows Alt code. The rest predate wide keyboard support entirely, so the HTML entity or the Unicode value is the only practical way to place them, either pasted directly or entered through an operating system’s Unicode input method.
Questions
What is the Alt code for the euro sign?
Alt+0128 on current Windows versions. Older builds without the euro update need the HTML entity, €, or the Unicode value instead.
Is there an Alt code for the Indian rupee sign?
No. Type it with the Unicode value U+20B9, or copy it directly from this page.
Why do so many currency signs have no Alt code?
The Alt code table was fixed decades before most of these signs existed. Unicode has kept adding currency signs since; Windows Alt codes have not.
Is there an Alt code for the Bitcoin sign?
No. It is a recent addition to Unicode, added in 2017, well after the Alt code table was fixed. Use the HTML entity ₿ or the Unicode value U+20BF.
Why does the dollar sign need no special code at all?
It sits directly on a standard keyboard, Shift+4, so it never needed an Alt code or a Unicode workaround.