[mrloba]

If you have different currencies you need to keep track of the number of decimals used, e.g. YEN has 0 decimals, bitcoin has 6, etc. It could even change over time like Icelandic ISK did in 2007. If you have different services with different knowledge about this you're in big trouble. Also prices can have an arbitrary number of decimals up until you round it to an actual monetary amount. And if you have enough decimals, the integer solution might not have enough bits anymore, so make sure you use bigints (also when JSON parsing in javascript).

Example in js: Number(9999999.999999999).toString() // => 9999999.999999998

And make sure you're not rounding using Math.round

Math.round(-1.5) // => -1

or toFixed

(2090.5 * 8.61).toFixed(2) // => 17999.20 should have been 17999.21 8.165.toFixed(2) // => 8.16 should be 8.17

The better solution is to use arbitrary precision decimals, and transport them as strings. Store them as arbitrary precision decimals in the database when possible.