QUINCY, ILL. -- It's the NFL's oldest rivalry, but these two enemies have only met once in the playoffs.

The Chicago Bears take on the Green Bay Packers at Soldier Field this weekend.

You might be planning on taking a train ride up there, but if you want to see the game in person, you'll have to pay up.

Some are calling it the toughest ticket ever to a Bears game. They sold out on Ticketmaster in about a minute. Prices on Stub Hub are anywhere from more than $400 for nosebleed seats in the corner of the upper deck, to $10,000 dollars for club seats.

"The main thing is to not become over enthusiastic to the point of paying exorbitant prices for something that even the best Chicago Bear fan, and Green Bay Packer fans, knows is too much," said Attorney General Spokesman Scott Mulford.

The Illinois attorney general is urging Chicago Bears fans to investigate playoff ticket sellers.

Attorney General Lisa Madigan issued the warning Tuesday, telling fans to be cautious and investigate ticket sellers before making online payments.

If you're dealing with a ticket broker, make sure the broker is a member of the National Association of Ticket Brokers and the Better Business Bureau. Illinois ticket brokers should be registered with the Illinois Secretary of State's Index Department.  Also, you should never wire any payment to a seller for any reason.

"If someone cannot tell you that they have the tickets, where the tickets are, or the face value of the tickets, these are all things to be cognizant of," said Mulford

She says customers should make sure vendors are members Consumers can file online complaints with the Attorney General's office. Fans also shouldn't pay strangers cash for tickets that could be counterfeit.

Along with tickets, fans also are making sure they have the right gear for the game. We stopped into M-C Sports in Quincy to see how their merchandise is doing. They have plenty of hats and Cutler, Forte, and Hester jerseys still. What they don't have are division champion shirts. Manager Angela Nixon said she doesn't know if they'll be getting any in.

"We have seen an increase, I would say, over the past three weeks. Unfortunately, we don't carry as much Bears product as we did in 2006 when they did go to the Super Bowl, but we have seen an increase of traffic coming in," said MC Sports store manager Angela Nixon.

Nixon also said they could get more shipped in, if the Bears make it to the Super Bowl.