I'd assume that it is a no-name gray box system. Such complete systems (without display) sell on eBay for $75 - $200.
It is possible, that you can make more money by selling the components separately (vs. a complete system).
Your system appears to have the following components:
1. A motherboard with 386SX-40MHz CPU. The reasonable price is something like $50. You might see much higher prices on eBay (up to $350). I don't think anyone in his right might would pay as much, unless they need to replace a motherboard an industrial piece of equipment, and need 100% compatibility.
2. 2 MB for RAM. Likely in a form of two 1 MB SIMMs - $8
3. ISA Multi-IO. Say $50
4. 40 MB IDE drive. Difficult to say... Not many drives survived from that time, but there are cheaper replacements available. Say $50.
5. A floppy drive or two. I doubt they are 8". More likely 3.5" or perhaps 5.25" for the system of that time period. 3.5" drives are still dirt-cheap - less than $10, 5.25" drives are slightly more expensive - $25 or so.
6. VGA controller. Depends on the type of the controller, but cheaper ones go for $30.
7. CRT VGA display, say 14" as they were really common during that time. $40. Shipping would cost more than the monitor...
8. Case/power supply... Not sure about this one.
9. AT type keyboard. Really cheap ($10), unless a high quality, e.g. IBM Model M.
There is always the alternative of keeping this part of computer history to yourself, and enjoying some late 80's games on it