For big, traditional publishers, these two numbers are correlated. An advance of $50k+ suggests that they take your book quite seriously and are therefore also quite likely to support it with a guaranteed marketing spend. Whereas a lower advance (especially of $10k or less, which is typical for unproven and unplatformed authors) suggests that they’re going to wait and see. Alternatively, some smaller indie publishers will compensate for lower advances by providing significantly more guaranteed marketing, which is also a fine deal.
