If you dreamed of the thrift shop, then it foretells about your past where you did not learn all of the lessons. Perhaps the dream wants you to remember some matters and include them in this time of your life. Maybe you just simply forgot what you learned, only now you are trying to get back to your past and remember all of those things.
Dream dictionary: thrift shop dream meanings
(Also see Used clothing)
…(Attire | Goodwill | Secondhand) Buying used clothing in a dream means poverty, but selling worn garments in a dream means good deeds, for in that case, one repels his aggravation or unwarranted adversities. A thrift shop salesperson in a dream represents a layman. Selling used clothing in a dream also means putting an end to one’s problems….
(Alms | Generosity | Secondhand | Thrift shop | Torn garments. See Used clothing)