Hi Clove,
The BEST way to market a how-to book is to establish a presence on the internet. You can do this at no cost. Start a Yahoo discussion group (I did this with a group called "WhizbangChickenPluckers" years ago and it now has over 2,000 members). Start your own blog (I have six of them). One of my blogs is actually a Whizbang Books "catalog," complete with ordering blank. My sales pretty much doubled when I made that "blogalog." As far as I know it is the only blog of the kind on the internet. And it cost me absolutely NO MONEY to do these things.
I do have a web site (www.whizbangbooks.com) but it is very simple and I paid very little to have someone else put it on the web for me. It acts as "Whizbang Central" and directs people to my many blog essays, which, as I've said, cost nothing to put on the web.
I have not used Ebay to sell books in a long time. But I did that when I started out and it certainly works. Besides selling books, Ebay listings can be used to direct people to your internet sites.
I have also used paid advertising in a few homestead magazines. But my objective with the ads is not to sell something as much as it is to get the reader to read my internet essays.
If I can do this sort of thing, anyone else can do this too. It just takes a lot of time and determination.
Best wishes.