MVP SaaS application: should I send out an email campaign to prospective users half way through development?

I have a SaaS application I have made a 6 months ago. A month ago, I decided to shut it off and upgrade it. I have shut the SaaS down so that I may do another launch as the first version was very was buggy (crappy website, product that stopped working).

From my previous MVP, I had gotten sign ups (users). Also, I built list from my old inbox contacts (old customers and other relevant contacts). Recently, I have started another mailing list (MailChimp email submit form). So that's 3 different mailing lists. In total I probably have about 1000+ emails to fire off to.

I'm about 60% finished with the new website and new product. I want to tell people about it but not sure what I should include in the email.

I also wonder if it's okay to ask for early paying customers. I might show them a few screenshots and a demo before I do this, but this time around, I don't want a large number of free users who don't end up paying or don't want to.

Which takes me to another discussion, my SaaS incurs a significant operating cost for each freemium user ($2~$20). If conversions are less than 5% for freemium users to upgrade to a paying plan, I feel it's unsustainable. (100 users costing on average $10 a month each) with 5 paying customers paying $50 a month each. Even if I raise the price by 50%, I'd still be underwater.

So my thinking is put off on the freemium plan for now and just focus on paying users and those that want to pay to use it. I'm going to include that I won't support freemium users which I fear won't be a popular decision but I simply cannot afford it.

I think you have several questions here:

1. Should you contact beta users before you launch?
2. Should you ask them to pre-pay for the service that is still in development and hasn't launched?
3. Should you have a free plan if your fix costs for each of those free users is high?

Here is what I would suggest for these questions:

1) You could email the beta users an update about your progress. Add something interesting or something of value that they will get out of your email.

2) Depends on the type of SaaS application, the rapport you've built with those users, and if you're going to do this manually by contacting each user. Kickstarter is an alternative if you want to raise some money by having customers pre-pay for something you're still building.

3) Those seem to be very high fixed costs for each account. What are you spending $2-$20 per free user on? If those really are your costs, I would suggesting launching with just paid plans -- and experimenting with a freemium plan later when you have a revenue stream.