Second-hand Smaco price

[Macguyverkevin]

Hello airgunners!
I am looking at a Smaco 300 bar compressor for sale second-hand. These seem to be pretty decent little units and I see typical new prices at approx. $499 or sometimes lower.
This one looks to be in decent condition, but I have no way to know how many hours it has, or if any proper maintenance (or abuse) has been done to it. I did get a chance to use it to charge my Texan up to 3000psi which took about 10 minutes from around 1500-1700-ish. That seems about right as far as I can tell.

So... with all that said, what would be a good price to negotiate - given the unknowns here?

I am reaching out to Smaco for any and all documents on it.

[Back_Roads]

 Never heard of them, looked them up seems to be a SCUBA supplier. Also appears to be a GX clone. Fill time seems about right, so it works.
https://smacosports.com/products/smaco-heap-1-air-compressor-oil-free-built-in-water-oil-sepa-12v-300bar-4500psi

[sb327]

It looks to be the same as a Gx cs3-I



Dave