I bought a Taylor brand electronic scale that goes to 12#s at Walmart about a decade ago. Great unit. Gets used for meat packaging besides gear weighing. Also for bows, firearms, etc. Keep a spreadsheet or notebook going as it ultimately helps you fine tune your pack. Also very handy to know how much fuel is left in used containers. Weigh them new, write the weight on the bottom of the canister, then re-weigh after partial use.
Got a postal scale on Ebay new for like 15 bucks. It's worked great.
I ship a lot of used gear and it's easy to purchase and print labels through USPS and schedule pickup. Beats going to the post office...