Yes you could use a shot glass or small glass vase, bud vase I think they are.
In my betta brandy sniffer I started out planting my lucky bamboo in a shot glass but it was too heavy for the shot glass, or maybe too tall?  Well anyways I went with the bud vase and it looks very nice.

This are lovely ideas, Mindemae. I love your betta brandy sniffer 
I will use the shot glass, as the driftwood would be too big, as you know our tank is only 38 l. It starts to be small for Humphrey and Hepsiba. So I need to compensate with using smaller decorations or the ones they can swim through and as I mentioned before maintain good water quality and aeration 

Those are lovely pictures, Hanna!
You can find all kinds of tiny glass vases, containers, etc. really cheap at resale shops or even yard sales.
I like to browse for unique things like that at estate sales or salvation army or goodwill shops too.

LOL!  Yeah mine do that too Eat and poop! 

Wow! $2 stores...you're getting robbed we have $! stores here!

That sounds like a good idea! That's a technique commonly used for ponds and such, but it should work fine in a tank as well! (:
For example in some brackish mangrove tanks they use to put the plants in terracotta pots that are concealed partly in the sand, partly behind bigger ornaments But you don't have to pick any big terracotta pots for your tank! xD Think it's fine with the little glasses you mentioned (: Guess you already tried putting heavy glass stones around the roots?

Hah, well, guess the pots should do the trick then!

Mindemae, this looks gorgeous, Well I am a cat lover too, I may like this one better than the brandy sniffer...
maybe you should have used it to sniff and slurp brandy out of it, LOL, yummm 

The glass I put in, doesn't look too good to me, thought it will be nicer  ,    will have a look at Sam's this arvo if I can find sth else, otherwise I think I'll use one of those rocks I already have, put the plant in that hole, so Humphrey can't get stuck like he did in the past.

How do you control the ammonia levels and so on in a tank that small for a betta? I know they don't need much oxygen in the water but just something I've always wondered.

Hahahaha, yes, they may get used to it, but it takes lots of photos to be taken until I get a nice shot and then I adjust contrast and brightness in Adobe Photoshop, crop the image so Hump and Hep fill the whole photo, more or less, 
I also wiggle in front of the tank and make them wiggle and stay there, LOL, my hubby thinks sometimes I'm nuts and he comments, LOL, " Hannaaaa you're not a fish in the tank..." and I cannot stop laughing answering him "wiggle, wiggle" and he responds "wiggle, wiggle, smiggle, smiggle, giggle, giggle"
You can imagine what's going on sometimes, we have soooo much fun ever since we got our fishies it is a funny crazy home here 

Hanna: The same here! Last time we went to my apartment and my fish weren't there, me and my fiance felt so lonely without them staring at our every move :'D Those fish are such a bliss!

 maybe you are interested in some "dream tanks"     (Link is not visible to guests. Please register to view.)

Thats an adorable betta bowl Mindemae! Kinda forboding too.. Makes you wonder what the fish is thinking everytime he sees the cat looking in on him.. !!!

I was wondering, Is a three gallon tank too too big for a betta fish? I mean, I want a betta but I dont have room for another bowl

You can keep a single betta in almost anything.  The problem with keeping a betta in like a community tank is that some will even challenge a fight with fish not even their own kind!  Like even a goldfish like sonorus could be challenged because they would see her long beautiful fins and think she is another betta.  They are so territorial and not very smart!  Betta males and females will fight but I think you can keep more than 1 female betta together. But definately not 2 males!

Nossie, which book is this?

Yes, ladies, that site just shows beautiful set ups