What version/edition of Toad are you looking to evaluate? If you're only looking at the Base version you can checkout Toad for Oracle Base Subscription. Download it from here and you'll get a 30-day trial automatically. This version of Toad is functionally equivalent to the non-subscription licensed Toad, Base model, which excludes some features only available in a higher tier like Toad Professional, Xpert, or DB Admin module.
If you're looking to evaluate the Professional version or DB Admin module or anything higher than the base model you'll need to contact Sales Customer Support and see if they can get you a functioning key. Please note that response times might be delayed this week due to the holidays.
Also, which version of Toad are you trying to gain access to? Please post the link from which you downloaded it. What is the error message you receive? We have some Quest folks on here that are more knowledgeable than me who might be able to provide a faster response time.