Yes, prices of new straps for the Modular 45 on eBay are usually well over the retail price
(which is €275 for the calfskin straps)
On the TH website there are only the straps for the current generation, but you can order them at your usual AD, at normal price
You can find here all the available straps with part number (starting with 1FT to fit the titanium buckle, and starting with 2FT to fit the black ceramic buckle):
http://customer-service.tagheuer.com/uploads/file/TH_TradeCat_2018-2019_EN_LR.pdfClick to expand...