I got gas today and it's showing as a $100 charge but I only spent $16. I have the upgrade one visa card. I know sometimes they do weird things at gas stations and correct itself a day later but I'm not sure.
It's probably the preauthorization charge that occurs at gas stations.
As @FlaDude said often gas stations do a pre-authorization of $100 then you pump the gas.
Later the real charge appears and the $100 dollar's goes away.
They test the card before letting you get the gas. 
Better a hold for 100 than you only having 10 on the card left.
Thanks everyone you were right. After making the post I noticed that my available credit was only showing me down $35 which was the correct amount because I used the card twice earlier today in order to reach my $400 bonus requirements.
What your looking at is the pre-authorization amount not the final amount. All transactions start with a pre-authorization and have the final amount come through in the next 2-3 business days. With most normal transactions where you know the final amount when your buying the two numbers are the same and will swap with one another. However when you have gas dispensers they need to check your payment exists before pumping. So their number will usually be as high as $150 depending on area until the final number comes in at the end of pumping. Also lots of gas pumps will have a more reasonable number if your a repeat customer with the same card. Similar things happen at restaurants with tips. Most will authorise the food only at first and add the tip later after. However some restaurants will automatically add %20 in the idea that they prefer to secure the whole amount as a pre-authorization still holds funds in your account but they are reserved for this transaction.
