My advice, from experience, is see your GP first and establish you need help. It is not over complicated. End of the day if you have any hint of ED then they are obligated to help you. I was prescribed Viagra and felt that it was best option because I was still capable of getting erections, just maintaining was the issue. I have had friends take Cialis and they seem happy. But it is generally a daily dose and depends on the level required. It seemed to me to be more medication than I needed. Most notable side effects from Viagra are the red or flushed face and mild headaches. Strangely for me, this only occurred when I took Viagra. After the first script I changed to the generic brands of sidelafil (maybe misspelt there) and basically swapped around each script. They were effective for me and I was using 50mg doses. Basically half a tablet. What I found was, that for me, it was best if I didn't eat prior and limited my fluids also. So punting was usually before lunch or before dinner in the end. All good. Rarely got 2 shots away but it was possible. Usually after the shower the erection was gone. Not sure about price varies as I never bought online. I am pretty sure the is an old thread asking for the same advice. Hope it helps. But like most things, what works for one may not work for another. Best to experiment till you are happy 👍