We didn't mean to insult you and nor did we accuse you of keeping your betta in a half gallon tank but from the title of your post you said that this was your first betta and so we were merely trying to help you by suggesting the cheaper betta, why? well because betta's aren't as easy to take care of as people think, their tails get damaged quite easily and they are prone to diseases. The owner can look after their betta as if it were the queen but they can still get infection or damage their selves with a plant, gravel, strong filter current or tail biting and as pet store betta's are quite old when sold this is even more likely IMO
When I first started out I had a £5 betta, it was a heated and filtered 2.5 gallon which I changed twice weekly but after just a month of buying him he died with fin rot IMO I did everything necessary, I fed him, gave him clean water and cycled his tank, so was he sold to me like that or was it my fault? So from that experience I will always recommend a £5 betta to a £30 betta as a first, now that I am more experienced I went for a more expensive betta but that doesn't mean I still don't ask questions, members that have been in this hobby for years still ask questions I'm sure.
What betta you buy and how much you spend is up to you and for the record... that pineapple looks gorgeous
and I apologise if I seem like I am blabbering on, I blame the wine lol