Hey! If you are US-based the cheaper and faster option is to use a service like clerky.com, they provide little to none customization but it's good enough for anything before a series A. After that I strongly suggest to use an international law firm, I've had good experiences with Bird&Bird and Orrick

The best source is by being referred by someone you trust.
If the people you trust can't directly refer you to a lawyer who can draft a contract to give to an investor, then they can refer you to someone who CAN refer you.

Writing a contract "to give to small time investors" could be a simple non-disclosure that is not meant to be enforceable, given to 2 investors potentially putting in less than $50,000 each, OR could be a full set of investment documents - private placement memoranda, subscription agreement, share purchase agreement, etc. given to 5 investors in order to invest $500,000 each (which would be considered 'small time' from the perspective of later stage VC's).

If its the former, its going to be inexpensive and almost any lawyer - and many non-lawyers - can do it.

If its the latter, its going to be expensive and you really want someone who is experienced and knowledgeable in this area FOR YOUR JURISDICTION.

The simple answer, if you are in the US, is a law firm that specializes in business law.

Hello - I would be happy to help you with that, I write contracts that stand-up and can PROVE it (with court documents) on a 7 figure case in which I was the Plaintiff there to defend my contract defended by a licensed attorney who took my case on contingency AND paid the filing fee's!

I offer decades of my own experience...
However, I am not an attorney - but have always had a necessity for them and an enjoyment reading/writing contracts!

Please feel free to contact me, if you feel I may be of assistance.