Its not great to buy oils on Amazon -- it's not regulated enough with items coming into their warehouses and there are stories floating around about receiving essential oils that have been cut wth carrier oils. I'd recommend either getting a gift card to somewhere like Edens Garden or going to Whole Foods or Vitamin Shoppe instead and buying a couple. I have never used any from WF or VS so I personally can't speak to how quailty they are.

As far as diffusers go, Ive tried several on Amazon and they've all been fine. This is the one Ive been using lately: https://www.amazon.com/dp/B0716SV4H1/ref=cm_sw_r_cp_apa_mffoAbK1CJXCK