Um, are we talking tip in respect to a gratuity on service rendered or tip as in good advice.
I'm thinking it's more likely the latter - as far as I know there are no elephant places on Tao. Ditto for the guided jungle walks (or unguided if it comes to that). I'm sure good ol' Google and Trip Adviser can tell you what's available on Samui.
If we are talking gratuities, I'd be thinking nada. The guide books will tell you Thailand is not a tipping country. Trouble is a lot of high end visitors can't help themselves. My take is - why encourage this insidious practice? I have worked for more than 30 years in a very demanding job with bulk personal confrontations involving very unpleasant people for poor pay. Nobody tipped me.
Thailand is a tipping country and has been for decades. I'm sure that Tezza didn't get 300 baht a day so there's no need for him to complain. Day trips vary in price depending on how far you travel and what you do. Boat trips from Samui are more expensive than other places. Elephant rides are around the 600 baht level in other places but I'm not sure about Samui. If you really want to trek into jungles best to head up north as the islands don't have much of that.
"Trouble is a lot of high end visitors can't help themselves. "
Average Thais tip other Thais.
What a tightwad. You have to work in a service industry (often low pay) to receive a tip. I can just see you counting your last 1 baht change. Pathetic. Thais slaving away working 6 days a week for peanuts and you're too lousy to tip them 20 baht while you're having a holiday every year. How selfish.