Hey, Tyler, I know you're looking to show your appreciation for anyone who offers to read your book, considering that you can't offer a swap at the moment. However, I do worry that offering money will only get you readers who are in it for the money, rather than the good will of trying to make your book better. Alternatively, it may make a beta feel like they have to do more than they usually would, basically working as an editor for less than an editor's fee. Betas are generally unpaid and don't expect any kind of monetary reward. There are plenty of willing beta readers who don't need a swap, but will beta something that piques their interest. A freelance editor, who you would pay money to, would do her best on your novel because that's her job and a good experience with her would lead to word-of-mouth business, but that's the not same service as a beta reader.
Why don't you scrap the monetary offer, and instead give us a few details about your book to see if you can catch the eye of a willing beta reader?