Should I have a sales contract with my first client?

Next week I will meet with my first client to discuss a subscription with my SaaS product. I gave him the first month to test it out.

During that time, he’s given me a wealth of helpful feedback and he's very pleased with what I've provided.

When I demoed the product, we discussed the trial period and the monthly subscription fee so there will be no surprises when we talk money.

I don't feel any pressure to bind him to anything legally. Even in the unlikely event he tells me "I don't want it", I can still walk away with a stronger product.

I was thinking, if anything, I would give him a sales contract that would benefit him. Something to the effect of:

1. Your rate will never go up
2. You will get grandfathered into any additional packages/upgrades that will be charged separately

I thought this might be a nice way of saying thanks for giving my product a chance and helping me create something better.

I also wonder if that's even necessary because I worry it may seem too formal.

We are not friends but we’ve known each other for months and I would describe the relationship as good acquaintances.

Should I walk in with a contract or not?

Firstly, you don't need a formal contract with the only purpose to cover your sales promises. You considered it because you don't have confidence at your words. Be confident, man, if you don't trust your words, others won't too. To cover your promises, an email should be good enough in most cases.

Secondly, I suggest never use "never", "forever". Your business may be sold, or closed(sorry for the bad word but that is possible), strategy may be switched, scope may be changed. If you have too much "never", "forever" sent, you'll have problems then.

You can have other terms to thank him for being your first clients and offered great feedbacks. For example, free or big discount for x months/years more etc.