Yoghurt, making your own

I do not like the yoghurt that you can buy at the grocery stores- too runny for me. I used to make my own using a spoon or two as a starter from a large cup of thicker plain yoghurt (~ 55 baht), labeled active bacteria, from TOPS. I have been to TOPS several times in the last few weeks to buy it, but they were out-of-stock. Sales people told us that they get delivery of that brand each Thursday. So, we kept on going on Fridays, without success in buying that brand. Unfortunately, we did not keep some of our own yoghurt to start a new batch.
Do you know of any other source of the type of yoghurt that I was using as a starter? Or, if any of you make your own, can you spare a cup for me to use to get going again?

Ray, interesting. I gave up on the idea of making my own because I couldn't find a place with the right temp. So I was really happy when Tops in Udon starting selling real yoghurt that is now easily available in Khonkaen, Bangkok and Pattaya.
And honestly, I have been succesful in Udon as well.

I always wonder what the stuff they sell as seetened and fruitened yoghurt is, can't be yoghurt can it ?

Where do you store the yoghurtcultures when making yoghurt, what is the temp. And what milk do you use, there is for my taste anyway quite a variety in the pasteurized section, I like Meji milk.

I make yoghurt and eat it with papaya as a natural laxative, something that perhaps a majority of ‘seniors’ can benefit from, especially if they are suffering from diabetes. I am not an expert in yoghurt-making, just an experimenter, but then there is no set formula for yoghurt making. With that caveat, I can share my experience.
I buy milk with 0% or 2% fat, any brand, Meji included. More fat in the milk equals to smoother yoghurt. Can add sweetener (honey for medicinal properties, but not for diabetics), gelatin (to make it firmer pudding-like) that I do not. I do not have a 'standard' (heating element-type) oven, I warm up the milk to near boiling in a microwave oven, then mix in the starter yoghurt (culture) into the warm milk, and if the starter came from the refrigerator, I warm up the mix again in the microwave oven; and then let it sit inside for a few hours. If I had a regular oven, I would have kept the mixture at 90-100C; I like firmer yoghurt.
I usually finish eating the yoghurt within a week, leaving a little starter for the next batch, or buy another box with active bacteria from TOPS. The product sold in stores technically is yoghurt, because added to milk it will curdle it, but barely; I cannot make it firm. For eating, it is runny which I do not like, plus it is loaded with stuff I do not want in my yoghurt.
Anyway, for more details and alternatives, you can consult Chef Google.