I have not gotten it but it is likely from GBO, more or less, anyway.
It is one of the ways the current owners make money on this site. Dunno if it's them selling e-mail addresses or if it's them sending stuff out for advertisers themselves. You can opt out of getting the e-mails from any one of them you get. I think I did that way back which is likely why I didn't get the one you guys are talking about.
However I do get that same e-mail often, just not from GBO. It's a common thing someone is sending out. They call it free, just want you to pay the shipping to get it to you. Shipping cost is the real cost and covers both their actual shipping of it to you and their profit. I've never actually looked to see how much the "shipping" is to get it to me as I don't want it.
Only scam in it that I see is they get your credit card info for the "shipping cost". Since I've never taken them up on the offer I don't know if they would make additional charges or not.
But any of the e-mails you get from GBO you can click a link and opt out of future e-mail. Clicking it won't do anything nasty to your computer and they really will stop sending them to you. It's all in the Terms of Use you agree to when signing up on a site like this.
Back when me and Matt owned the site we didn't do stuff like this, these days pretty much all site owners do such things.