Making a roll-on perfume with fragrance oils is a simple process that requires a few basic supplies. Here's how to do it:

1. Gather your materials: You will need fragrance oil, a carrier oil (such as jojoba oil, sweet almond oil, or fractionated coconut oil), and a rollerball bottle.

2. Choose your fragrance oil: Pick a fragrance oil that you like. There are many options available, ranging from floral to citrus to spicy scents.

3. Mix the fragrance and carrier oil: In a small container, mix the fragrance oil and carrier oil in a ratio of about 10-20% fragrance oil to 80-90% carrier oil. The exact amount will depend on the strength of the fragrance oil you are using, so you may need to adjust the ratio accordingly.

4. Store the mixture: Let the mixture sit for 24 hours to allow the fragrance to fully mix with the carrier oil.

5. Transfer to the rollerball bottle: After the mixture has been stored, transfer it to a rollerball bottle.

6. Enjoy your homemade roll-on perfume: Roll the perfume onto pulse points such as wrists, neck, and behind the ears.

Note: It's always important to follow the instructions and warnings on the fragrance oil packaging, and to store the perfume properly to ensure its longevity and safety.