Hey @Mikal. The reason is that you are looking at different futures contracts on Oil, which are two different instruments. The one on our platform with a price of ~18.50$ is with expiration in April, whereas the one selling at ~25.60$ is set to expire in May.
I strongly advise you to educate yourself on the nature of futures contracts and their trading conditions before entering in any positions on them. You can also check the video below:
I hope this will be of help. Cheers.