Here’s a little trick I’ve used in D&D games where the premise of your campaign calls for the party to have access to lots of Stuff, but you don’t want to do a whole bunch of bookkeeping: the Wagon.
In a nutshell, the party has a horse-drawn wagon that they use to get around between – and often during – adventures. This doesn’t come out of any individual player character’s starting budget; it’s just provided as part of the campaign premise.
Before setting out from a town or other place of rest, the party has to decide how many gold pieces they want to spend on supplies. These funds aren’t spent on anything in particular, and form a running total that represents how much Stuff is in the wagon.
Any time a player character needs something in the way of supplies during a journey or adventure, one of two things can happen:
1. If it’s something that any fool would have packed for the trip and it’s something that could reasonably have been obtained at one of the party’s recent stopovers (e.g., rations, spare clothing, fifty feet of rope, etc.), then the wagon contains as much of it as they reasonably need. Just deduct the Player’s Handbook list price for the item(s) in question from the wagon’s total.
2. If it’s something where having packed it would take some explaining, or if it’s something that’s unlikely to have been available for purchase at any of the party’s recent stopovers (e.g., a telescope, a barrel of fine wine, a book of dwarven erotic poetry, etc.), the player in need makes a retroactive Intelligence or Wisdom check, versus a DC set by the GM, to see if they somehow anticipated the need for the item(s) in question. Proficiency may apply to this check, depending on what’s needed. The results are read as follows:
Success: You find what you’re looking for, more or less. If the group is amenable, you can narrate a brief flashback explaining the circumstances of its acquisition. Deduct its list price (or a price set by the GM, if it’s not on the list) from the wagon’s total.
Failure by 5 points or less: You find something sort of close to what you’re looking for. The GM decides exactly what; it won’t ever be useless for the purpose at hand, but depending on her current level of whimsy, it may simply be a lesser version of what you were looking for, or it may be something creatively off the mark. Deduct and optionally flash back as above.
Failure by more than 5 points: You come up empty-handed, and can’t try again for that item or anything closely resembling it until after your next stopover.
As an incidental benefit, all the junk the wagon is carrying acts as a sort of ablative armour. If the wagon or its horses would ever take damage, instead subtract a number of gold pieces from its total equal to the number of hit points of damage it would have suffered. The GM is encouraged to describe what’s been destroyed in lurid detail.
This type of method makes it *way* easier to keep track of items, and… it’s pretty darn funny when the players succeed a roll to see if they backed something outrageously stupid. Trust me, the flash backs are hilarious. Never skip out on them.