I believe Contax III was the first 35mm camera to offer a built-in meter, which puts us in the mid to late 1930's.
It does add considerable bulk to the camera body.
My first "real" 35mm camera was my Retina IIIc, with built-in meter... it worked/works well.
A bit "fiddly", but not an extra gadget bouncing around on a lanyard.
That said, my prime shooter nowadays is a Leica III (1934). I have a hand-held meter in my kit, a Toshiba CdS from the late 1960's, which looks like a copy of the Gossen Luna-Pilot. It is a good, compact meter.
Prior to getting the Toshiba (box-lot of meters from eBay), I was using my Gossen Luna-Six, a fine meter, but twice the size of the Toshiba.
Generally, when I'm out shooting, I get a general reading, then estimate from there, untl there's a significant change in the light. I do not meter every shot.
This has worked well for me, but then I'm not out for money-shots or "art"... and I generally shoot the same film (Kodacolor 200).
I am a little reluctant to leave the meter at home and go "Sunny - f/16", but that's due to lack of confidence. I keep a Kodak Signet 35 RF in my '61 Rambler, and I do not have a meter when shooting that - so far the results have been acceptable.
I've seen the clip-on Leicameter M and CV clip-on meters, and they don't appeal to me right now, being an LTM shooter. I usually shoot with an accessory finder (Nikon Vari-focal), so my camera shoe is ocuppied by that device. Given the cost of the CV double-accy shoe plus the CV meter, I could buy a new CV 21mm LTM lens...
I've acquired a couple of small selenium clip-on meters ( Leicameter 2 and a Koden clone), but both have dead cells, and I don't think they are worth the investment to repair.
I seem to be doing just fine with my hand-helds.
You can probably find a used CdS meter in good order fairly inexpensively; try to get one with an incident light diffuser built-in (Gossen)...
Good luck !
LF