Wait, wait, from what is there to read the summoning of a Demon is a bit different from a standard ritual.
In a standard ritual you need different tools like bell, chalice, athama, incense and clothes fit for rituals and yes you don't need all of these given the world of today, you have clear instructions on rituals but how does one proceed in Demon evocation? You just put the sigil on your table and recite the prayer, sorry for being dumb but I need to make sure everything goes okay.
Another thing is specific incense is kinda hard to find but given the fact that they are used as perfume does that mean that scented stick with the specific aroma for the specific God can be used instead?
Black clothes, should I use only clothes used for rituals or less used clothes after they are washed? I don't mean any kind of pijamas but because of the jewflation even the most basic clothes are becoming expensive but they are still affordable.
Another thing is that you need an altar for doing rituals but the space in my house doesn't permit one, like really there is no possible way to do that sadly, the most I can do use the bench from my pc as a temporary altar and put my stuff there...
The chalice, they are also expensive but affordable, even so does something else can be used, like a glass?
Also what is there to give to a God, yes I know that energy or promises of advancement can be used what if after a God was summoned there is someone else to ask for help, you can't offer the same thing twice... :(
Yes, just the prayer, and have their sigil. I understand your concern to get it right, but after you do a few summonings you'll feel more confident about it :)
For incense, yes the stick with the aroma. This is optional though, as some people are sensitive to scents.
You don't need to have clothes just for summoning, you can wear nice clothes that are clean. After a while I saved up and bought a robe that I only use for summoning and rituals.
You don't need an alter. Your computer bench will work just fine, or sit comfortably on your bed with pillows behind you to prop yourself up. This might be better, as you can probably relax and tune in easier like this, rather than at your desk.
You can use a glass for a chalice, or just visualize one, like on the astral or in your imagination. This is what I always did.
As for what to offer the God in return, this can be some publicity. For example, write a post here thanking the God, mention your experience (unless this feels too personal). Do an extra Ritual or another God ritual (it can be Zeus's Ritual if we don't yet have the ritual for the God you summon). Or any other idea that comes to mind during or after the summoning :)