1. Show me your price, with multiple pricing tiers. The more tiers you have, the more likely I am going to pick one of them, because I will think "well this lower tier is quite the deal compared to the higher tiers!". If I am an Enterprise customer, I will disregard you as an option if I can't see a price. Don't even show me the tier at all if you aren't going to show me your price. I get immediately incensed when I see that "Contact us for pricing!" bullshit, because I know how much bullshit I am in for if I just want to get a quote, so I look for somebody else. I want to use your product right now. But I'm not going to use it if I think it will be painful to work with your company, or that you might have exorbitant pricing, or you're just looking for whales. Don't make me discount you.
2. Let me use your product, immediately. Let me run it from my laptop immediately. Let me spin up a PoC. Show me your complete reference docs immediately. Show me a toy implementation w/source. I want to know if this will [eventually] give me what I want, within 15 minutes. Do that and you will already have gone above and beyond 95% of SaaS (in my mind).
3. Let me have gradient pricing. Let me sign up right away and start using your product for $0, for 5 users. Send me an e-mail when I have 7 users, informing me that I have 30 days to either reduce the number of users to 5, or it will automatically upgrade my account and charge me more (or make me confirm, or whatever). Same for the next tier, etc. (or 'pre-purchase' discounts vs 'on-demand' overage cost, etc) This gives me flexibility: I know our workflows won't just stop working when we hit a limit, and I can acquiesce to the new price or clean up old users.
4. Let me start using your product without a card on file. Sometimes it takes a while to find the right corporate person with the right corp card (if they even let me use a corp card, rather than invoicing). If you really need a card, give me 15-30 days, and then pause my account if you have to. The point is to let me get "hooked" on your product without needing to figure out which card to use first. (It goes without saying that when the card expires or a charge doesn't go through, give me 30 days to resolve it, because usually the corp card has hit its limit)