Both freebase nicotine and salt nicotine is suitable for use in all mouth-to-lung vaping devices. The nicotine shots are intended for use with shortfill e-liquids and not to be vaped straight.
Many of the 10ml e-liquids are available in multi-buy deals. This is shown on the product image which will state how many can be purchased at a discounted rate. Feel free to mix and match different brands if they fall within the same deal.
If you're having a hard time deciding which e-liquids to go for, then why not have a look at some of our most popular brands.