Burial urns in Skyrim are mostly empty, and when they are not there is 5-7 septims in it while in real life, urns usually contain hundreds of gold pieces.
Of course, if I put a thousand septim in all urns it would not be balanced and it'd be too easy to earn your money. Instead, I changed the levelled loot system a bit and added a base of 40, 20, 15 and 10 septims, depending on which kind of urn it is and how other you encounter one. Added a burial armour and a burial robe (which is very rare, Nords are not exactly mages), no you cannot wear them, but you can sell them. All urns now have a burial weapon, simply draugr weapons but their damage and value have been decreased because who would want to buy a weapon stolen from a dead person? No new textures, just simple draugr armour and weapons. There is a chance of finding jewellery and gems in urns as well as finding potions and spell tomes.
In the rarest type of urn (with the base of 40 gold pieces):
At level 1 you get 40 gold pieces, Burial armour or robe, One of the three burial weapons and maybe a potion (small chance)
At level 60 you get 80+ gold pieces, Burial armour or robe, One of the three burial weapons, a random gem, quite possible a necklace.
At level 1000 you get 400 gold pieces. That's what Creation Kit says even though I have no proof of this one.