It would be best to call the library before making a financial commitment. I've emailed many libraries recently and most tell me that their contract with Overdrive prohibits them from giving cards to out-of-state residents. Some still do but others had to stop. If you do call, make sure you explain it would be for ebook downloads only.
Regarding Orange Cty: Many of their books are YA and romances so make sure they have the titles and subjects that interest you. They do obtain multiple copies of titles.
You dont say where you live but many county libraries have reciprocal agreements with neighboring ones.