ATM Buying New/Used Eyepieces

[BBird@basspro.com]

Can anyone give advice on buying new/used eyepieces from web advertisement.
Bad idea?  Trustworthy sites/people?  I'm looking to replace my original
Coulter Kellner 27mm eyepiece with a Meade 26mm SP series 4000.  One ad
claims he has such eyepieces made in Japan which are superior to the
current made ones.   What's the deal with Japan versus China/Taiwan made
Meade eyepieces?  Secondly, I'm looking for a medium power eyepiece in the
15-22 range (have a 12.5 mm orthoscopic from Coulter that is great cause I
do wear eyeglasses).  Same person with several ads of Meade eyepieces also
has a 18mm Meade Wide Angle of 5 lenses instead of the 7 lenses in the
current Meade Super Wide Angle.  I'm looking at the used/ad market to save
some bucks but if that is not a good avenue then perhaps the beginner's
Sirius set (26,17,10) from Orion.  Any advice/warnings/suggestions would be
greatly appreciated.  My scope is an Odyssey 8 f4.5 built back in August
1987 and now getting more light cause my kids (starting in 1988) are
getting interested in using it.
Clear Skies!
Brad Bird