1 Galleon equal to 20 Sickles or 1000 Knuts.
20 Sickles equal to 1 Galleon or 1000 Knuts.
1000 Knuts equal to 1 Galleon or 20 Sickles.
___
1 Galleon equal to 100 Pound.
20 Sickles equal to 100 Pound.
1000 Knuts equal to 100 Pound.
___
A Working-class Wizarding family in Magical Britain and Ireland might earn 300 Galleons annually.
The best source of income in the Wizarding World is Dungeons.
___
House Malfoy's Legal Net Worth: 320.000.000+ Galleons. [320M Galleons]
The Malfoys are probably the richest or one of the richest Pureblood Houses so you can calculate the wealth of other houses based on this.
___
Muggleborns may convert Pounds or any other Muggle currency up to the equivalent of 100 Galleons annually.
Hogwarts has a scholarship for under-resourced Muggleborn students, which helps students access adequate supplies.
The reason Hogwarts is able to provide this scholarship is because Houses that are sympathetic to Muggleborns and Muggleborns who have graduated from Hogwarts support it.