Depends if you're after pure efficient range xp or just want to use them.
Ideal 'value for money' would be to get a slayer task at catacombs - either dust devils or abby demons, group them up then chin them.
For range exp, as stated previously by 2 - go to the manical monkeys tele.
This is the set up i've used in the past. It's not the greatest but gets the job done.
https://i.gyazo.com/...662d48ba470.png