If you're interested in purchasing oil-based lubricants, there are a few things to keep in mind:

1. Check the ingredients: Look for products that use high-quality, safe ingredients. Avoid any products that contain potentially harmful chemicals like parabens, glycerin, or propylene glycol.
2. Choose the right type of oil-based lubricant: Oil-based lubricants are great for use during sex, but they can damage condoms and increase the risk of infections. If you are not using condoms, then oil-based lubricants can be a good choice. However, if you are using condoms, you should use water-based or silicone-based lubricants instead.
3. Consider your personal preferences: Oil-based lubricants tend to be thicker and longer-lasting than water-based or silicone-based lubricants. However, they may also leave a greasy residue and stain fabrics. Consider your personal preferences before making a purchase.
4. Look for a reputable brand: There are many brands of oil-based lubricants available, so it's important to choose a reputable one. Look for brands that are known for using high-quality ingredients and have good reviews from other users.
5. Store the lubricant properly: Oil-based lubricants can degrade over time, so it's important to store them properly. Keep the lubricant in a cool, dry place, away from direct sunlight and heat sources.

Overall, buying oil-based lubricants requires some attention to detail and consideration of personal preferences. If you have any concerns or questions, it's always a good idea to consult with a healthcare professional or sex educator.