In most cases, a new correctly cut key (NOT a duplicate of one of yur other keys) will solve that problem.  It may also require cleaning and lubrication.  This is a common occurrence with keys that are 5-10 ngenerations old, combined with crusty locks.  We can handle the key and cleaning/lubricationg or you can do the cleaning yourself.  Do NOT use WD40 or graphite.
Steve Sandlin,
Steve's Lock Shoppe
84 Wolfsburg Westy Subaru
79 bus
74 412 wagon
00 New Beetle
License # B12682