There are two kind of those heater levers.  The early ones (like on my '84) have the small rubber tips that tend to come off.  The later kind have a bigger rubber tip that seems more robust.  I could not figure out how to fix mine so I bought some new ones from Bus Depot and so far so good.  I see them ocationally for sale on eBay and the Samba classifieds, but like you say shipping is a factor.  I just ordered them when I needed other things from the BD because it was not like they were a "have to have now" part.  
Pascal
"84 Westy

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From: Vanagon Mailing List on behalf of Mark Hoffmann

So one of my four heater/air control levers has had the tip get loose and pull off. It's made of a soft rubber or plastic and it fits right back on but pulls off easily. Is there someone that has had this happen and found success glueing the end back on? New ones don't cost that much but add shipping, etc. and I figure that someone knows what the fix is for less.