@boomlover I would say Cor, as it was the currency in Aincrad in SAO.
"Cor can take the form of physical coins, known denominations include a silver coin worth 100 Cor, a gold coin worth 500 Cor"
Just for some values that were used in SAO in terms of how expensive things were in that game:
- 1 Cor - The cheapest dry and unrefined black bread purchased from an NPC bakery.
- 30 Cor - The amount of Cor that can be obtained by defeating a single Frenzy Boar in the field.
- 50 Cor - The price of renting a room in a 1st Floor Inn for one night (less than 6 jō tatami mats or 100 square ft). Comes with one bed and a table.
- 1,000 Cor - The amount of Cor that can be obtained by defeating a Lizardman Lord on the 74th Floor.
- 100,000 Cor - The minimum price of a custom-made weapon made using special ingredients by Lisbeth(For our RP, probably any skilled Blacksmith).
So when using these values, try to gauge a... reasonable amount. Mobs don't drop that much money as you can see from the relatively low increase in money gained from a Boar to Lizardman Lord.
Unless
@NightmareInd has a different idea for currency and value, I think Cor would be a good place to start.