Spells are just manifestation rituals with props.
The most important thing is setting your intention, visualization and accessing the emotion you wish to bring in.
Spells use symbolism to draw out certain emotions or help you visualize certain things and stay focused.
For example, you may use rose petals, rose water or rose quartz in a love related spell since roses are associated with love, and will be a physical representation of this to you as you do your spellwork.
As long as you are not trying to take away anyone's free will or inflict harm, you should be ok.
But I would not pay anyone else to do a spell as you do not know what they are actually doing for you, if anything.