@Chino de Oro​ @redxps630 

Okay thank you so much for your responses. What about a Dell Optiplex 7040 Tower? Would it be capable of holding the power supply and graphics card I mentioned before?

@Chino de Oro​ Thank you so much. Just found found a 7040 Mini Tower that fits in my budget.

The 7040 is not a full-size mini tower and won't fit a full-size ATX PSU.  See screengrabs.

PSU in a G5 5090 (9th gen) or G5 5000 (10t gen) can easily power 120w GTX 1660 TI. The newer Optiplex towers also have optional somewhat higher-watt PSU's.

If your budget is a little more limited, a Precision 3620 (6th and 7th gen) with optional 365w PSU* can power your card.  *290w standard

If budget is allowed, OP can get a full tower Precision 5820 with 950w power supply for less than $200 USD.  This is an example system that is available today on the big auction site.  It came with a Xeon CPU which is equivalent to a Skylake i7 processor, 16GB ECC memory, 1TB NVMe SSD, 950w PSU, and Windows 11 pro.  Just replace the basic Quadro video card with a GeForce card and it's ready as moderate gaming machine.

So, basically, instead of spending a hundred dollars or more for almost 1000w power supply (and a 24-pin cable), just put that investment toward a system which has better future upgrades potential.  There are two different 5820 systems:  Xeon processors with C422 chipset motherboard and Core-X series processors with X299 motherboard.  Many enthusiasts have selected the Core-X series for gaming and causing it to cost slightly more.

This is just a suggestion input with idea for OP to think about.

The Optiplex minitower 7040/50/60/70 use clam shell style chassis which is not great for full height video card.  

A proper Optiplex  minitower w gaming pc potential would be either 7080 and later, or legacy 7020/7010/790 MT case.

Notwithstanding the enthusiasm on Dell precision by my co volunteers (RS or not ), I do not recommend it.  They are of a totally different class from Optiplex.  

@Chino de Oro​ 

That Precision 5820 is an impressive find.

Thanks Brad.  Just happened to see it while looking for a Core-Xtreme unit.  The release of high core count desktop processors in recent years in combination with Dell offerings of AMD high power Threadripper for workstations have killed off all the value of those earlier release workstations.

Now that Dell just stopped selling the 5820, they worth almost nothing (compare to original value) after being off lease.  Workstation enthusiast such as yourself may consider another upgrade soon! 

That may explain why I got my 3620 for $80.