Although this does not help with your tree at ancestry, tribalpages allows you to highlight family lines (hint for the ancestry team - little colored squares next to the name of the person in the index that represents that particular line, ie. blue for John Smith's family and red for John Doe's) and at the bottom of each page the forebear and the colored square that represents the family line - sort of like a navigation bar, you can access the family by clicking the "navigation bar" - would be such a great asset to your customers)
The "free account" at tribal allows 1 (pesky ads with this option as well as other limitations); the $24 annual allows 4; the $36 annual allows 8 and the $48 annual allows 16.
If your goal is exposure as well as being able to attach a record as a source without doing the extra work (spelling out the citation rather than attaching a record found on ancestry), ancestry is the best place to host your tree.
That being said, you may also want to consider tribalpages as the fee is pretty reasonable and you have more control over how your tree is accessed as well as how it is presented.
Kind regards and happy hunting!