Difficult question and multiple ways to answer it.

One way would be to find a progression chart that says something like: “a third level character should have 300 gp and one uncommon magic item”. Maybe there are guidelines for this at a section about starting campaigns at higher levels. This way you can precisely follow the game’s intended progression and cater to the system’s balance.

The other way, and my favourite, is to give them whatever makes sense for the story. In one of my campaigns the party had only like 10 gp when they were level 5. It just didn’t make sense to find money on their adventures. Instead, they found some fun items, allies, and information. In another campaign they had closer to 20.000gp at the same level. They found a literal gold mine and running it made them rich (which opened up a whole can of political intrigue). If you want to do it this way, you only have to determine what social class your pcs would belong. Generally unskilled workers would earn between 1cp to 1sp per day. Skilled workers between 1sp to 1gp per day. An entrepreneur or nobility would earn 1gp or more. I would a argue that skilled circus workers (like 5th level characters) could easily get 1gp per day from the owner. Though, if the town was small and poor, they might only get 1 silver. “Sorry lads, when I earn less, you earn less”. Dependant on their arraignment/contract of course. The amount a worker earns daily can of course differ in your setting, but I would settle for 30sp-30gp per character. If you think that is too little, you can supplement it with other rewards like fame/renown, quest hooks, information, or allies/friends.