LOL...I take advantage of the economy and tell them that the budget for that item has been spent until next year! Few vendors will waste time talking to someone with no money to spend!
Unfortunately, most of the time it's true!

If it's a product or vendor I know I'm not interested in, I say "I don't want to waste your time--thanks for calling" and then I hang up. I'm sure it sounds a bit abrupt on the other end, but I expect at least some of them do appreciate not spending a lot of time on a dead end.

I am a librarian who worked on "the dark side" as a vendor for a few years. Here;s the thing - don't make excuses every. Telling a vendor you're going into a program or saying you're not interested is not a NO. Same as asking for information. TI means I might be interested and the vendor will follow up.
Be straight. My observations from the other side taught me that most people, not just librarians don't give the straight forward response a vendor needs to hear to take you off the cold call list - if only for one year. KEep these things in mind too: Many vendor sales reps are also librarians and are knowledgeable about how libraries function, some are professional sales types who may or may not get it.

Vendors have territories and competitors in their territories. If you're in the vendors's zone you're gonna get pinged because that person is looking to increase business, to take it away from a competitor. They'll call it see if your library's business is status quo - if there are changes of people, of money, of programme.

SO.. bolttom line - if you are not interested in a particular product be straight - Thanks for the call. We don't need/want/have any interest in your product at this time. Please don't call back for at leat a year because I know this won't change. NO I don't want your information yet I know you have a web site and I'll check there.

I have taken to kindly advising pushy vendors that their time would be better spent with a different customer.

If you are the director, also make sure you are using your staff as a resource. Make sure that when staff takes a call for you, they get the vendor's name and company. You can then tell them to take a message if you don't feel like talking to the person.

Otherwise, I agree with the others who said to say, "Thank you, I'm not interested," and then just hang up.

Vendors just like librarians have a limited amount of time. They will understand no with a reason. The no money reason works but I feel the "not in the process of buying" reason better. Everybody says they have no money but sales people understand process. I am new to librarianship but very very very old in sales. I like to tell them politely no and then refer to them a date and time they can call back. Normally 6-9 months hence.

I explain that our phone rings in the Library classroom and therefore we will not accept vendor calls because it disrupts teaching. They are welcome to snail mail us but we will refuse all phone calls. This works for almost everyone but the lightbulb guy. He is a real dim bulb because I told him we don't buy bulbs, the building engineer does, and yet he calls regularly and I hang up on him every time. If you have a real pest, simply tell them they will be put on the Library "Do Not Buy" list if they call again. Snail mail only!

I also find it helpful when I go to a big conference to create a gmail account to give to vendors. This avoids my library email inbox from overflowing with solicitations in the weeks following the event. A month or so later, I can sit down and weed through all the emails at once, create rules to dump the vendors that I don't think I'll ever use, send a handful of vendors to my main email, and after six months close the account completely

I have one pushy vendor with whom I've already tried several of the tactics mentioned above and she still calls constantly. So now every single time she calls I tell her I have a program about to start. Even if it's a really oddball time like 1:13. She still hasn't taken the hint yet.

You can always ask for a catalog. Tell them that the Board has to approve any purchase, so you need to see a catalog. Usually they'll take your information and send it away. Of course, then you have to worry about throwing away junk mail, but I'd rather throw away junk mail and deal with pushy people.

I am a librarian who took on the electronic resources coordinating in my library about 2.5 years ago. I am amazed at the unprofessional vendor sales out there! A few of them are as bad as used car salespeople. I am really annoyed at how difficult it is to get pricing on their products, too. It would be so much more helpful for them to just post their pricing scale or price somewhere easy to find, like their web page. So, my advice is that if they are ramping up their "pushiness", then feel free to push back. They are wasting your valuable time and theirs as well.

That said, I have had really good results by using the "out of money for the year, etc" excuse. Also, for medium-annoying sales reps (for products I am possibly interested in), I have been successful at the "call me back on a future date" excuse. I push a lot of calls to the next fall semester. Just tell them to call you back after beginning of fiscal year, and this usually works (half the time they don't). Vendor sales reps have high turnover it seems. Also, I always insist on them emailing or snail-mailing their info. Since they seem to always want to get you on the phone (where you are vulnerable), this might slow them down a bit.