Looking for a good organizational tool or basic CRM. Hopefully free (I work alone)

I’m a one man show, solo worker. Im a travel consultant (I customize each and every itinerary for clients) and need to handle maybe several dozen clients at one time (inputting several new leads per day). Need to input all of their personal details, their details of their travel plans, logging each and every call and email, keep track of tons of note taking (after calls or just thoughts I have), itineraries (sometimes several revised ones), changes and adjustments, etc.

Right now I’m using OneNote and it’s getting messy. It works but i do need a better tool. i’d prefer just some free version if possible since it’s only me and very basic needs are needed.

Any thoughts out there? thx!