To all the gamblers out there, there is hope.
I haven't played in 3-5 months, and found out you can sell NX pssb items. Sold a couple items worth $10-$20 and wanted to roll on a vac pet. I found a sure fire way to get a vac pet on the first 6 boxes.
Step 1. Make sure you have an irl pet
Step 2. Give pet treats
Step 3. Tell pet he's a good boy/girl
Step 4. Stroke the pet
Step 5. Roll
With this method I hit on box #6. Good luck gamblers
Edit: Make sure you repeat these steps per roll.