Gold at higher levels can often be somewhat a moot point anyway, 5e has it's rarity system and attunement caps to throttle the spending of players on high level and powerful items. At lower levels it depends on your setting like Vanguard says, if you are playing a low magic world then the economy should more accurately match that of medieval Europe with most people and therefore monsters having very little in terms of financial wealth but potentially with an accumulated wealth of 'heirlooms' or emergency potions etc. The top 1% however would have an abundance of items, money and gems but would rarely part with it. In a more magic rich environment I would rule that gold is a bit easier to come by, the economy naturally saturated by scrolls, potions and low level/borderline useless magic items. As a DM in that world I would ensure that the players have things to spend their money on that are in that borderline useless category but that flavour to their particular tastes... got a noble? How about this fine automatic tent, erects itself in seconds complete with camp bed and fire pit... yours for only 200gp, last one in stock! As they level and items before naturally harder to purchase (after-all, who in their right mind is going to sell a rare or higher item without a very good reason!) I try to give alternative ways to spend, let them buy, staff and run a ship/airship (they can then use that in the pursuit of desired high level items rumoured to be in the trove of a particular dragon etc). Let them set up a guildhall, hell, even found a town... being a hero is more than just slaying monsters and saving the world, its about the legacy ;) In terms of figuring out how much to give, don't over think it, give what feels right or use a generator/DMs Guide rules... PCs will always find a way to ruin all your plans so just roll with the punches and as long as everyone is having fun (including you!) then there is nothing to worry about. (Final note, the Roll20 forums are designed for discussing the VTT specifically so this thread might get closed by a mod at some point... Reddit is always a good shout for continuing this though)