Clients, even consumers, already mail 20 providers in BCC, asking for a quote, then pick the cheapest or the best blend, according to them. Which is usually very different from what a choice based on professionally relevant criteria would be.
The cheapest is something you can't help, unless you want that to be you. And you don't, because someone's always going to work for exposure or experience if it comes to it. Or for fun. You can't possibly be the cheapest unless you pay them.
But you can help the best blend. The blend is a sweet spot. The sweet spot where supply best meets demand, or so the client thinks. The best fit.
By saying more about yourself, accurately and in an encouraging way if you can help it, you can't convince mass askers. Not often at least. But you can persuade people away from masking. Or you can convince them before they mass ask.
You can make them think that you're the only option, or the best, or just good enough so there's no need to look further.
My personal take is that the less ambitious, more modest target of 'just good enough so there's no need to look further' is a good, solid base to cover before you fiddle with the fancy stuff. First the basics, then the extras — if at all.
We may all need this if the trend for getting multiple quotes, even on small jobs and even by consumers, continues to rise.
That, and, of course, we need to stop gambling our precious time with the 20 other people in the BCC field. Doesn't mean we should give them exactly zero time, though. Nope. There is a war to wage, so there are battles to fight.
It is good to have a canned response in which you state just what your rates would be for the same job in normal circumstances, while refusing to enter the battle of quotes. This is the least you can do to help unteach them the bad thinking habits, such as that they can get a special (i.e. reduced) offer for just asking and for just being them. Y'know, everybody is special, but so is everybody else. And his dog.
Still, show them you considered their inquiry/requirement/need individually, but the size of your fee is based on standard applicable rates.
Else, if they keep only getting responses from people who are prepared to play their game, they'll end up with a distorted view of the market, thinking everybody else is unavailable or uninterested and those who do respond represent the industry opinion as a whole. Which is not the case (or so I hope).
Thank you for your interest. It is my policy not to participate in competitive quotes. This e-mail is emphatically not a bid.
For reference, my standard applicable fee for your particular request (as specified in your mail) would be XXX.
Always feel free to contact me for a specific quotation or booking. Please, however, keep in mind my policy not to participate in competitive bidding.
Just an example.
If you feel like it, you can consider adding something to the tune of:
Please be aware that due to the low statistical probability of having the project assigned to me out of all of the providers asked for this quotation I am prevented from being able to spend as much time preparing a more tailored quote as is normally the standard of care I give to my clients.
And yes, not a single comma. Be confident. Transmission, not dialogue. And certainly no arguing or pleading. Just remember to turn it into generally acceptable passive-aggressive corpobabble without showing a genuine human side.