Your newly acquired plants are established in their present pots, but their roots systems have not used all of the space in their pots. They should live and grow in these same pots for at least another few months to a year before re-potting will be necessary. When transplanting, choose one pot size larger. Excess soil in too large a pot may cause soil to sour before roots can grow into and utilize it. Gently tap the plant out of its present pot. Gently brush or scrape away some of the old soil around the root ball, taking care not to disturb the center of the root ball or to break roots. Put some soil mix in the new pot and place the plant on top. Gently fill in around the sides; keep the plant at the same level as it was in the old pot. Let the plant stay dry a few days. This precaution will allow any roots that are damaged or broken during the transplanting process to heal and callous over before watering, avoiding rot of broken roots. When watering, let drain thoroughly.
For handling and transplanting smaller plants, thin rubber gloves can be used to protect the fingers. Tongs also work well. Larger plants can be handled with a short section of hose wrapped around the plant, or even a rolled newspaper can be used.