This has to be the most laudable trait anyone can possess. Think of all the beauty that accrues from this pursuit. It is my practice never to remove seed heads from my flowers til the next spring...nature has done any necessary vernalization (saves me work) the tropicals are different however...has anyone brought an African violet to seed and actually harvested progeny? May I recommend this... try it, it is very satisfying but a slow, patience testing process. Seed pods, once formed, need 6 to 9 mos. to mature. (yes growers do it every day but it is a real coup to accomplish this in your kitchen!)
I get small ziploc baggies from my local craft store, using the coupon in the paper for 40 or 50% off. If you're on the email lists for these stores, they will email you coupons sometimes, also. I reuse the baggies, so as not to waste and add to landfills.
ziplocs and a sharpie...don't leave home without them.
WalMart has little zip-top baggies, 100 for 97 cents... just be sure you're looking in the craft department, usually near beads & jewelry findings.
Sharpie marker will wear off plastic bags with time & handling. I've gone to using paper label slips inside the bags. For temporary use, I stick a marker and a few sandwich baggies in my pocket -- I know those seeds will go in paper bags or on plates for drying once I get back inside, and after I clean them they'll go into the little zip-top bags.
You're right to try to always have something with you -- in a pocket, purse, glove compartment, etc. Some folks carry pretty extensive seed collecting kits with them in the car once seed-collecting season is underway. :-)
Thanks for your response! It's always fun to meet a fellow seed snatcher. :-)