First 10 minutes
Drain a few buckets with the Standard Bucket to confirm the F-key teleport and token earning. Then buy the Plastic Bucket as soon as you have 200 Gems from your first hidden chest.
Skill Tree priority
Capacity is the strongest first upgrade. Fill Speed starts to matter once you have a Plastic, Metal, or Toilet Bucket. Depth nodes should be saved until you have a stable loop.
When to roll the Bucket Wheel
Do not roll the Bucket Wheel until you can comfortably afford the Magnet Bucket (1,200 Gems) from the vendor. Toilet and Toxic will still be common drops later.