Advertising - your feedback welcomed

This is a request to my readers as to your thoughts on advertising.

Advertising on websites is, I know, a thorny issue. I chose to place some ads on my site a while ago,  to generate some modest (I can assure you, extremely small!) income possibilities that will allow this blog to expand and continue.   I also set up the merchandise store for the same reason.   I would like to think that I haven't gone overboard with the ad placement, but really, that is for you to tell me.  The intention was to use any money generated to either:

a) buy uke accessories (or even ukuleles) for reviewing on this site, hence expanding the reviews section (a part of the site that gets the most traffic)
b) to consider expanding the site and perhaps moving it onto its own webspace at some point in the future.

I have also added a PayPal donations button on the right hand side - if you feel you wish to say thanks or try to support the site (in however a small way) that would also be appreciated.  Heck, you could buy me a beer!

But again, is the donation button in conjunction with the google adverts too much?  It isn't, of course, mandatory!  Let me know what you think.

All feedback is gratefully received!