In Steal a PC, your base has two upgrades that change how quickly you grow. The pen sets how many boxes and PCs you can hold, which caps your passive income. The treadmill sets how much speed you gain per second while you run on it. Speed decides which zones you can raid and get back from. Both upgrades cost cash, and cash comes from PCs sitting in your pen. Each upgrade feeds the other, so the order you buy them in matters.
Quick answer: Pen Level 7 → 8 costs $24M (+1 slot), and Level 8 → 9 costs $320M. Treadmill Level 2 → 3 costs $770K, and Level 3 → 4 costs $2M.
Steal a PC pen and treadmill upgrade prices
Each upgrade panel shows the current level, the next level, the price, and what you get. Treadmill upgrades can be bought with cash or Robux. The pen tiers below are listed with cash prices.
| Upgrade | Level change | Price | Effect |
|---|---|---|---|
| Pen | Level 7 → 8 | $24M | +1 slot (12 → 13) |
| Pen | Level 8 → 9 | $320M | +1 slot (13 → 14) |
| Treadmill | Level 2 → 3 | $770K or 8 Robux | +1.32K → +3.37K Speed/s |
| Treadmill | Level 3 → 4 | $2M or 12 Robux | +3.37K → +21.2K Speed/s |
The two upgrades scale very differently. Pen prices climb steeply. The jump from Level 8 to Level 9 costs more than thirteen times the previous tier, and it still adds only one slot. Treadmill prices rise slowly while the payoff grows fast. Level 4 more than sextuples your Speed/s compared to Level 3, and it costs just $2M. Early on, treadmill levels give you far more per dollar.
How to upgrade the pen when it fills up
Pen slots hold both the boxes you are hatching and the PCs that earn money. Every placed item takes one slot. When all slots are used, the game blocks any new placement and shows “Pen full (13/13)! Upgrade it at the board.” The number changes with your level. Once you see this message, a pen upgrade is the only way to hatch another box without removing something first.
Once you reach Level 8, the board’s next offer is the Level 8 → 9 upgrade at $320M, again for a single slot. At that price, swapping weak PCs out for better ones usually raises income faster than waiting to afford the extra slot.
Treadmill upgrades and the speed each zone expects
The treadmill only builds speed while you are on it. Step on, and the game shows “Running! Press Space / Jump to get off.” Your Speed/s rate depends on your treadmill level. After an upgrade, “Treadmill upgraded to Lv.3!” (or whichever level you bought) confirms it, and the new rate applies the next time you run.
Speed matters because each zone has a recommended speed. Below that number, the trip back to the Safe Zone with a stolen box gets risky. Here are the first four zones on the route out from your base:
| Zone | Recommended speed |
|---|---|
| Grass | 5 |
| Forest | 1.5K |
| Mushroom | 67.5K |
| Desert | 650K |
The gap between Mushroom and Desert is almost tenfold. That is where treadmill levels pay off. At +3.37K Speed/s (Level 3), building toward 650K takes a long time. At +21.2K Speed/s (Level 4), it goes much faster. Two other speed modifiers sit on the base screen. “x2 Speed” costs 3 Robux, and a Friend Boost reads +0% when no friends are on your server.
Trails Shop speed multipliers
Trails are the third upgrade path. Each one multiplies the speed you gain, so a better trail makes every treadmill level worth more. You can buy them from the Trails Shop with cash or Robux, and your current trail is marked as equipped. Lime Streak (x1.5) is a common starting point.
| Trail | Rarity | Speed gain | Price |
|---|---|---|---|
| Cloud Puff | Common | x1.2 | $500 or 2 Robux |
| Lime Streak | Common | x1.5 | — |
| Ocean Wave | Uncommon | x2 | $1M or 8 Robux |
| Blaze | Uncommon | x2.5 | $50M or 19 Robux |
| Galaxy | Rare | x3 | $2.5B or 55 Robux |
| Sunbeam | Epic | x5 | $100B or 75 Robux |
| Frostbite | Epic | x6.5 | $1T or 99 Robux |
| Inferno | Legendary | x8 | $10T or 119 Robux |
| Plasma | Mythic | x13.5 | $75T or 155 Robux |
| Black Hole | Mythic | x16.5 | $300T or 179 Robux |
| Infinity | Secret | x20 | $1Qd or 219 Robux |
| Lightning | LIMITED | x40 | 240 Robux |
Ocean Wave is the obvious first cash buy. It costs $1M, about the same as a treadmill level, and it takes you from x1.5 to x2 gain. Lightning is a limited Robux-only trail with a stock counter (952 left at one point), so it can sell out. Above Blaze, cash prices jump into the billions and trillions. Those trails are long-term goals, not next purchases.
The trail multiplies speed gain, so it stacks with your treadmill level. Pairing Ocean Wave with a Level 4 treadmill boosts both parts of the same calculation.
Earning the cash for each upgrade
Every upgrade is paid for by the PCs in your pen. Your base shows its total rate as a banner, such as “Your base earns $25.6K/s offline!” Raising that number shortens the wait for the $24M pen tier or the $2M treadmill tier. To raise it, you steal boxes, hatch them, and keep only your best PCs out.
A single swap can make a real difference. Adding the Disco Dune PC ($10.9K/s) raised base income from $25.6K/s to $31.1K/s. Other PCs show their own rates, from the Sundial PC at $23K/s down to the Toadstool PC at $6.97K/s and Sandstone at $6.62K/s. That spread is why a full pen of weak PCs is often worth less than a smaller set of strong ones.
Box resets, night spawns, and offline income
Box supply changes over time, which affects how quickly you can afford the next upgrade. A server-wide “ALL BOXES RESET!” message refreshes the stands and can spawn Secret boxes in later zones, such as “A Secret Cosmic Box spawned in Cosmic!” and “A Secret Prehistoric Box spawned in Prehistoric!” At night, a countdown appears (“NIGHT TIME! New boxes in 9s”) before fresh boxes show up at the glowing stands.
The earnings banner says your base earns “offline,” so the PCs in your pen keep counting toward your next pen or treadmill tier after you leave through the Roblox menu. Before you log off, run Equip Best and fill every slot. That way, the highest possible rate is running while you are away.
