I use old or cheap candles melted in a roasting tin and dip the log ends or roll bowl blank edges for the bulk of mine. Wax held just below the fuming point boils off some of the surface moisture and sucks the wax tight into the surface which seems to help bonding.
Keep my eyes open for end of season sell offs in stores and discount shops.
If Branches etc. too big to handle by dipping I use any old paint leftovers, have been known to pick up the odd can of gloss end of line from the bargain bin, good for colour coding different batches.
Some folks use cheap PVA wood glue, basically anything that will stay on and provide a barrier akin to the bark to slow the moisture loss will do.