It is one of the most sought-after skills among RuneScape players
If you are talking about an opportunity to sign-up whereby people can sign up and RS Gold later draw random numbers and provide the winners with the code (with none of the strings or without any other information) This would be considered acceptable.
A donation to charity is perfectly acceptable. A trade of favours however is not. Yeah am talking about Subscription codes. I have seven subscription codes (I think I have them, but I'll have to double check) which I will not use therefore I was able to donate them for those whom cant afford to buy one.
I thought of doing something as follows: Create a thread about the giveaway and then I'll post questions such as. Why should I give you a membership? Why do you enjoy Runescape? What are you planning to do with the Membership? These questions will make it easier for me to select the best option and stop members from selling the codes or to prevent lazy spammers from getting the codes.
"Normal" (as in not Nex) GWD armour is sufficient to complete Slayer-related tasks. It's not a lot of money (for people with resources) it doesn't have to be replaced and also gives offensive advantages. Keep a Barrows set in every type of combat (Verac's as well as Ahrim's and Karil's) for the very few Slayer tasks that require armored protection of a high quality.
Glacor boots are the best boots for the moment. Barrow gloves are not very excellent anymore. They're hybrid gloves and can be used in a variety of ways OSRS Items, but if I were you I'd opt for the TWW automation gloves (Static Pneumatic, Tracking and Static). They are the gloves equivalent of Glacor boots.