@William *******
you're very welcome. Not to be morbid -- I too hope to slip the mortal coil in Thailand, many many years from now -- but if that's your plan you should make arrangements at your local temple in advance, and make sure the people where you are staying know about it. Won't cost you too much and you can avoid being a burden. Too many restless ghosts about as it is.
And back to the visa, lots of people will tell you to do it yourself, and that's a totally valid option. If you qualify and are well organized then it really is cheap and quick. But if you're disorganized, or moslty-qualified, or just strongly dislike dealing with immigration, then keep in mind that many people use agents, it's quite normal here, and we consider it good value for money. Others disagree about the value proposition, and they do without agents, and that's fine -- you should choose the route that makes you happy.