My computer. It cost me $3000 when I got it custom-made, then another $400 for the monitor, but that was 6 years ago. But since then I've added another NVMe SSD (a Samsung 980 PRO 2TB with heat sink), 16 more GB of ram, a couple of external drives (a 2TB SSD and a 6TB HDD), an RTX 4090 (that's over $2000), a $100 keyboard, a $300 keyboard, and a mouse with a cool color-gradient-changing LED strip around it. If it counts, I also have a $400 amp connected to a $500 pair of speakers connected solely to the computer. Oh, and a $90 subwoofer that I got for less than $20 at a yard sale.