It's been a big week for Big Mac fanatics.

Thursday, McDonald’s gave away 10,000 bottles of its signature Big Mac Special Sauce for the first time ever in the U.S. to celebrate the release of two new sizes of its bestselling burger.

For those who missed out earlier this week, you can score some Special Sauce-- but it won't be cheap. Since Thursday, unopened bottles of the sauce have been popping up all over eBay. As of Friday morning, a“big mac sauce” search on eBay yields over 370 restuls.

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Though most bottles appear to be going for around $100, one bottle is listed with a starting bid of $50,000-- or a "Buy It Now" price of $100,000. Should anyone decide to blow some serious cash on this bottle, the seller has agreed to donate 20 percent of the profits to March of Dimes if the bottle is purchased at full asking price.

Want another chance at a bottle of Special Sauce? Bid on #10,001 today until 8PM EST, 100% of proceeds go to @RMHC! https://t.co/soVcbn0iKY pic.twitter.com/rO0eEwMrjY — McDonald's (@McDonalds) January 27, 2017

If you don't want to get into a digital bidding war, McDonald’s has donated one last bottle to The Ronald McDonald House Charities (RMHC). RHMC will be auctioning off the Special Sauce bottle number 10,001 on Jan. 27. On Friday, that special bottle had already garnered eight bids.

McDonald's is using its big Big Mac momentum to try out another new idea in New England. A restaurant in Boston is preparing to launch a Big Mac ATM popup that will allow customers to be served without any human interaction, according to Eater.

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The burger-dispensing ATM will only be available for one day on Jan. 31 to promote the new Grand Mac and Mac Jr. Customers won’t have to turn over a dime for the burgers, just their Twitter handles. The machine will then send out a promotional tweet from the customer’s Twitter accounts in exchange for some beefy goodness.

After months of regional testing, McDonald’s launched the new Big Mac Trio nationwide on Jan. 26.