3 Goblins is a CR 1.333 round down to 1. Goblins have standard treasure. For a CR 1 encounter it is 260 GP. A single bugbear is CR 2 with standard treasure the CR 2 encounters have 550gp. The Assasin vine is CR 3 and incidental treasure which is half the amount for it's CR. CR 3 is 800 so half of that is 400 gp. Not every encounter needs to have treasure. User the WBL guidelines. For example 1 party getting to Level 2 should have about 1000 gp in treasure. So assume a party of 4 that is 4000 GP.
So you will want say 10 encounters. 2 APL -1, 3 APL =, 3 APL +1, 1 APL +2 and 1 APL +3. Throw in 2 CR 1 traps. End with a story award of XP to bring the PC to 2nd level. The APL -1 fight have no treasure as they are vermin. The APL = are 3 sets or 3 goblins, with 780 GP. The APL +1 is 3 set of 1 Bug Bear each with 1650, APL +2 is the assassin vine with 400 gp and the APL +3 is level 1 bugbear cleric with 1150 gp. Comes out to 3980 gp. That is almost the WBL for level 2 characters and the party is just over half way to level 2. So to balance thing you make some of the loot sold for 1/2 price. Stuff like masterwork weapons and armor. Then add in consumable magic items. Do this for about 1/2 that treasure. Do another adventure like this doing the same thing and players should be right on WBL guide line about 1000 GP give or take 100 gp.