You should also check your tenancy agreement – but even if your contract bans switching, Ofgem's guidance on this states that if you pay the energy bill, you're still entitled to change supplier any time. You can still compare on Cheap Energy Club if you don't have the former occupants' bills, just hit the "don't know" button when you enter your usage.
There are over 60 different energy suppliers competing for your business on any given day in Texas. Many of these electric companies have websites that are confusing and nearly impossible to navigate, their rates and fees hidden by dense industry jargon and misleading advertising. Who has the spare the time to sort through the choices spread out over all these different sites and companies?