There is one workaround option, although it shouldn't have to come to this as the technology exists for eBay to implement changes to the site which would result in seller offers only being sent to people who have the item saved on their Watch List. However, given that eBay haven't implemented this I can only conclude that either they're too lazy to make the changes or they simply don't have the brains to figure out how to do it!
What I would suggest is that until such time as eBay actually solve this problem - which, at present, looks to be extremely unlikely - if you want to look at something on eBay then when you open up your computer delete your browsing history from the past twenty-four hours, past week, or however long you feel is necessary to get rid of any previous record of your eBay browsing history. Once you have done so have a look at eBay, but without logging in. If you see an item that interests you to the point where you woud like to add it to your Watch List or purchase it make a note of the listing number.
Once you are done browsing items for sale, shut eBay down and then delete your browsing history from the last twenty-four hours. That way when you next sign into eBay there should be no record of your browsing from when you were not signed in. Using the listing numbers of the items you were interested in use the Advanced Search function to locate each item in question and either add it to your Watch List, or purchase it, depending upon what you want to do. Before logging out of eBay when you are actively signed in delete everything from your Viewed Items folder.
Finally, once you have finished with looking at eBay whilst you were logged in, log out again and delete your browsing history from at least the past twenty-four hours. If eBay can't tell which items you were looking at in the first place then they cannot harass you with unwanted offers, although if you placed an item on your Watch List they could potentially still send you offers on one or more of those items.
