Hold on a minute. 

If you're mailing something in an envelope, what's the primary goal? To open the envelope, of course. Then, to pay attention to what's inside. 

So what's the point of using a cheap, white envelope that doesn't stand apart from any other mail the recipient receives? It's called positioning, Folks. What can you do to stand out from everyone else? Going cheap with little image doesn't cut it. 

As far as bulk rate is concerned, I have a question for you. What do you do with bulk rate that arrives in your home or office mail? Immediately File 13, right? Then what makes you think people will pay attention to you, just because you spent the money to do a direct mailing? 

What's sauce for the goose is sauce for the gander. 

Here's the rub.
Too many business owners approach their marketing, whatever the strategy, by asking themselves the following question: "How cheaply can we get away with doing this?" 

And, where image counts, so that you may receive the attention you deserve, going cheap is not going to produce the results you're wishing for. 

Another direct mail hint: 

No one-shots. Mail at least three times, either bimonthly or quarterly; six times would be even better. 

You see, there's something I named "The Delay Factor" decades ago. The Delay Factor is the time between when your message appears in whatever form and the recipients respond. A very common response is, "You know, I have to contact them... when I have the time." With all that we have on our plates, there's little reason to believe that a one-time mailing will do the trick. 

Clients tell me repeatedly how they've just heard from someone they met at a trade or home show two years ago. A variation on that is when the client has finally made a decision, after taking 18 months to get to that point. 

Build a brand. Be consistent with your colors, your fonts, your messages. Give yourself the opportunity for others to receive/see/hear your promotional messages and say, "Oh, that's so-and-so. I recognize the paper stock/graphic design/musical introduction." 

Playing it cheap is not the way to stand out these days, not when there is so much clutter out there. 

Last point: there's no law anywhere on the US books that demands a mailing go out in its entirety within 48-72 hours. Mail 100 pieces per week. That will give you an opportunity to follow up on 10% of the pieces mailed within seven days, with some good open-ended questions. Yes, it's difficult to reach people these days; that said, sending a few a week and following up judiciously on a consistent basis will get you far more than a one-shot mailing done cheaply.