Couple points;
First is a rant of mine - whenever possible, I try to buy from my local dealer. I am usually willing to pay a reasonable "premium" for the personal service and knowledge I get from the dealer. Establishing a relationship with a GOOD dealer is well worth the small cost and time. If the dealer is way out of line price wise (does happen sometimes), I get stuff online or big box, but give the dealer a chance first....
Second, seems like quality is hard to find at a reasonable priced anymore with new products. Things don't seem to be built to last anymore. Products that "quit working after a few years" are common. When available, there is often a premium price for heavy duty quality. Seems to get out of "cheap" (no offense intended to those who are happy with this level product....) transaxles, engines, frames, etc, you need to go to the premium ($$$$$) level of the product. Deere products are expensive. Traditionally, this price premium was justified because the product was built to last (I still use a mid 80's garden tractor...). But this was before Deere started competing with the "less expensive" box store models.
I know it's not what the OP was asking for, but perhaps the cheapest option may be to rebuild his "old" tractor, or get another older machine. Garden tractors from the 80's and 90's are relatively cheap to buy. They are usually heavier built, simpler to maintain, have rebuildable parts and can be bought for pennies on the dollar.