Back in Austria 20 years ago, the first bikes that could be considered as real one were about 36.000 Baht. And good (enough) 60.000 Baht. Of course no upper limit. Easily you could spend double, triple that amount.

(taking the old exchange rate and my memory. I went to school at this time and built mine mostly from second hand parts, left-overs, etc. So these prices could be wrong even at this time if having a closer look).

Are these values somehow in the range for a bike only or are things generally more cheap or more expensive?

(only naked bike)

Depends on what you're looking at, I think you can get a decently spec'd aluminium road bike from Giant/Merida/Trek with 105 starting at around 25k+. Personally I'd go with something like Giant Defy or TCR in this price range. Great frame, and can upgrade parts/wheels later for better performance when you're ready without having to bin the frame.

Specialized is way overpriced here, otherwise I would recommend them as well.

A thing like this? (MERIDA SCULTURA 904, 29900 Baht), from an online shop:

http://www.km8bicycle.com/store/product/view/%E0%B8%A3%E0%B8%96%E0%B8%88%E0%B8%B1%E0%B8%81%E0%B8%A3%E0%B8%A2%E0%B8%B2%E0%B8%99%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%AB%E0%B8%A1%E0%B8%AD%E0%B8%9A_MERIDA_SCULTURA_904_%E0%B9%84%E0%B8%8B%E0%B8%AA%E0%B9%8C_47_50_52_cm_%E0%B8%AA%E0%B8%B5%E0%B8%82%E0%B8%B2%E0%B8%A7%E0%B8%99%E0%B9%89%E0%B8%B3%E0%B9%80%E0%B8%87%E0%B8%B4%E0%B8%99_%E0%B8%8A%E0%B8%B8-25538543-th.html

Overview of Merida models:

http://www.km8bicycle.com/store/product/%E0%B8%A3%E0%B8%96%E0%B8%88%E0%B8%B1%E0%B8%81%E0%B8%A3%E0%B8%A2%E0%B8%B2%E0%B8%99%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%AB%E0%B8%A1%E0%B8%AD%E0%B8%9A%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%A0%E0%B8%B9%E0%B9%80%E0%B8%82%E0%B8%B2_MERIDA-1156567-th.html

A thing like this? (MERIDA SCULTURA 904, 29900 Baht), from an online shop:

http://www.km8bicycle.com/store/product/view/%E0%B8%A3%E0%B8%96%E0%B8%88%E0%B8%B1%E0%B8%81%E0%B8%A3%E0%B8%A2%E0%B8%B2%E0%B8%99%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%AB%E0%B8%A1%E0%B8%AD%E0%B8%9A_MERIDA_SCULTURA_904_%E0%B9%84%E0%B8%8B%E0%B8%AA%E0%B9%8C_47_50_52_cm_%E0%B8%AA%E0%B8%B5%E0%B8%82%E0%B8%B2%E0%B8%A7%E0%B8%99%E0%B9%89%E0%B8%B3%E0%B9%80%E0%B8%87%E0%B8%B4%E0%B8%99_%E0%B8%8A%E0%B8%B8-25538543-th.html

Overview of Merida models:

http://www.km8bicycle.com/store/product/%E0%B8%A3%E0%B8%96%E0%B8%88%E0%B8%B1%E0%B8%81%E0%B8%A3%E0%B8%A2%E0%B8%B2%E0%B8%99%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%AB%E0%B8%A1%E0%B8%AD%E0%B8%9A%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%A0%E0%B8%B9%E0%B9%80%E0%B8%82%E0%B8%B2_MERIDA-1156567-th.html

Actually its a real shop, and the service there is very good if you can get one of the staffs attention, as generally they are always overflowing with customers. Also an excellent bike, although I personally prefer the look of the Lampre team edition, even it only comes with Tiagra group

http://www.km8bicycle.com/store/product/view/%E0%B8%A3%E0%B8%96%E0%B8%88%E0%B8%B1%E0%B8%81%E0%B8%A3%E0%B8%A2%E0%B8%B2%E0%B8%99%E0%B9%80%E0%B8%AA%E0%B8%B7%E0%B8%AD%E0%B8%AB%E0%B8%A1%E0%B8%AD%E0%B8%9A_MERIDA_SCULTURA_903_%E0%B8%AA%E0%B8%B5%E0%B8%94%E0%B8%B3%E0%B9%80%E0%B8%82%E0%B8%B5%E0%B8%A2%E0%B8%A7%E0%B8%97%E0%B8%B5%E0%B8%A1_LAMPRE_%E0%B8%A1%E0%B8%B2%E0%B8%94%E0%B9%89%E0%B8%A7%E0%B8%A2%E0%B8%81%E0%B8%A3%E0%B8%B8%E0%B9%8A%E0%B8%9A%E0%B9%80%E0%B8%8B%E0%B8%97TIAGRA_10SP_size_50_52_54_56_59cm-25187381-th.html