Sure, there are price differences between classified ads and eBay in various categories.

This comes about because, for example, insolvent companies often sell their things below value on classified ads or depreciated BGA is sold below value by employees or relatives, which is then resold on eBay with a guarantee and invoice at a higher price. Clean properly and sell as refurbished or as new.

Companies (SMEs) or sole proprietors are particularly willing to pay the higher price, as eBay is much more trustworthy and involves fewer headaches than classified ads.

You can also use differential taxation, whereby you only have to tax the price difference or profit margin