Dude, even though you have deleted your post, I completely understand.
When you are selling items on this website, all people do is lowball. It gets me that within a hobby where some people are ready to spend thousands of dollars on equipment and then also hundreds of dollars on livestock that will likely die anyway, come on this website and have the audacity to message someone with the prices they have in mind. I have to refrain myself from calling most people names. In a rare event, someone will actually message you with the price you had asked for or offers close and is reasonable.
This is not a cheap hobby, but beggars on this website definitely make it seem so.
Sorry you are having to deal with this.
No joke, have had people ask me for free Coral, going as far as specify high dollar pieces, have had people agree to buy a full sump setup and then only buy say the sink and flat out tell me they can't afford the skimmer or return pump because they are financially irresponsible. That's a quote. The worst is that I do commission setups and have people begging me, have seen the word begging used multiple times, to drive out 2 hours (1 way, for free....) to their house to take on a job no sane person would attempt in the first place. Been asked to put a full glass eurobrace on a newly set up but used waterbox (on a budget..) been asked to do trigonometry to figure out if a 36 inch sump would fit through a xx" cabinet door opening without any other measures. Plumb a sub 30 gallon sump to a full 300g tank using half inch plumbing......
I have made some good sales though and met some decent people, but prefer my local Reef club. No matter how you look at it even getting a 40 gallon breeder, a used overflow and converting a 20 gallon into a sump using the cheapest material you can get you'd be lucky to start a tank for 500 and that's before you start putting livestock Rock and Sand in it. It's a harsh reality I had to face myself with my first tank. And then no matter how much time, money or research you put into everything something will go wrong on your first tank. Algae outbreak and the ugly phase, hitchhikers. Not in the least bit forgiving compared to freshwater.
Lesson is know what you're getting into first.