Imaam Ishaaq bin Raahwayh (rahimahullah) once mentioned, “When Imaam Ahmed (rahimahullah) was travelling to study Hadith under Imaam ‘Abdur Razzaaq (rahimahullah), his wealth depleted and ran out. He thus hired himself to some camel drivers (and worked for them while travelling) until he reached San‘aa. The companions of Imaam Ahmed (rahimahullah) had offered to share their wealth with him, but he had refused to accept it.

(Siyar A’laam min Nubalaa vol. 9 pg. 458)