csgosavages is the site. I am not into gambling skins but it seems active. I have googled the scam and can see it happens often with a few minor differences. my skins are rubbish anyway and he happened to ask the guy who questions the smallest of gambles (2p slot machines? we all know you lose in the end
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If it seems too good to be true it probably is, some common scams to avoid are;
1. "I own a gambling site / I'm an admin on a gambling site!"
2. 2 guys add you, one guys wants a specific DOTA2 item which he'll give you his knife for (worth a lot more than yours), the other guy has said item and will send you a trade offer. This can be elaborate whilst they try to butter you up over a few days
3. DOTA2 items in general, just avoid trading as people an craft items themselves and put them on the market, making them appear as being worth much much more than they are
4. Adds from random profiles, as soon as you accept a link will be sent to you with "I really wanna trade your item, <click this link> to see my items!"
5. Random adds you, saying they need a 5th to play on their team and give you a teamspeak IP, DO NOT CONNECT TO THIS TS SERVER!!
6. People wanting to buy via PayPal, even if they go first they'll just chargeback!
7. People having a very sought for item in their inventory, ask you to send them an offer via the trade link they have on their profile text, which leads to a different account, with a different variant of the item worth much less, i.e. worse float/condition/pattern/finish (doppler sapphire vs p4, ruby vs P2 etc)
There are so many, and it's amazing that people fall for them. I asked one guy who tried it on me last week from the states, he claimed to have scammed 200~ people. I always give them an ear full ^^
Sometimes leading them on can be funny though.