Most sales people during their career will come across Customers or Prospects that will use you for your knowledge. They know you're pretty good at what you do but that possibly you are a little bit more expensive.
They will ring and ask for a quotation but with no details, generally because they themselves don't know the specifications, for example; "Can you give me a quote for a Laptop?". Now like the good little trusting person you are you will spend the next 10-20 minutes tracking down a machine, maybe make a couple of calls for prices and availability and type out the details all at the expense of your employer.
Having done a good job you will expect to 'get the order' but Oh no Mr Customer has just used you! They are now cutting-and-pasting your hard work into an email and asking all your competitors to quote! Now I suppose most people would say "And whats wrong with that?" apart from the fact that it tends to make you distrust Customers when they place an inquiry with you it also makes you want pay back.
I recently quoted for a Toshiba laptop true I put some markup on it thats how we make money for gods sake, anyway I gave some of the specs and part of the model number, about 20 minutes later I received an email "Can you give us the full model number?" Why? What difference does that make? Oh hang on you want to see if you can get it cheaper.
Cutting a long story short they went and purchased elsewhere, "I'm sorry Pete I can get it way cheaper" yeah after I did all the leg work for you. A week later a had an email
Customer: Can you transfer all the data from the old laptop to the new laptop?
Me: Sure, if you drop it off it will be £35 per hour if we collect and return it will be 1 x £65 + £35 per hour.
Customer: But we are only 20 minutes away
Me: Yes but if we do any work away from our premises we charge £65 per hour
Again cutting a long story short we went and collected the two Laptops and transfered the data such as files, folders and emails plus I backed down a little and charged £35 per hour. Blow me if the following day if I didn't get yet another email.
Customer: Can you send someone out to install TNT and Warehouse Management software.
Me: Yes this will incur a cost of £65 per hour
Customer: But we've already paid!
Me: No this is additional work you require
Here's the point, if they had purchased the Laptop from me I might have been a bit more willing to do the additional work and not charged them, as it happens they have ended up paying more than I would have made if they had purchased the laptop from me in the first place not because I've been vindictive but simply because they have done everything in their power to get as much as possible from us for free!
Getting the best deal for your company is one thing shafting your supplier is another Customer care is a two way street you look after your supplier and they will look after you the customer.