If you are only after basic tvs, Dick Smith will do a good price on quantities. They have a commercial department. https://www.dicksmith.com.au/about-dick-smith/commercial-sales
We have had 19 of their branded tvs for over 2 years no problems on any of them. They do not have a hotel lock and, if you have Foxtel, the user has to switch between analog and digital. Also they are not smart tvs (internet).
At the low price these units are I wouldn't bother with extended warranty.