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Jon: While those links are what I'm willing to do in the interests of seeing my books nominated and selected, I consider that list beyond minimal. A lot of us in Canada actually use the US store for historical reasons, and very few, if any, non-Australians have AU accounts. OTOH, if you're annoyed by the current pricing of back-list books and WhisperSync deals in the US, it's just plain smart to have a UK account.
To answer your question directly -- minimal links, to my mind, are an Amazon and a Kobo in your native country. I don't think overdrive links are terribly useful, since, in most cases, you can't actually see what's available outside your own country, and it is, in any case, entirely library dependent. But I provide a base link for Overdrive if it shows in my account. I also provide a page count taken from either Amazon or Goodreads. These appear to vary widely across editions but at least give you a ballpark length.
An alternative, for those struggling to provide meaningful links, is to PM one of the other regulars to ask for a link. I've indicated my willingness to search out links for AU, CA, UK and US accounts on at least Amazon. And US/CA for Kobo, though I rarely, if ever, buy from them any more now that the days of good coupons are history. I'm willing to help with links because I know just how difficult it can be to do this on a handheld device.
I don't think it's fair to expect our fearless leader,
issybird, to go hunting up links and prices. She already does more than enough just keeping everything posted and running. So I would suggest that those who care about their nomination, but have difficulty providing links and/or prices, should ask one of the other regulars if they would oblige.