Green’s Dictionary of Slang

tow n.

[SE tow, strands of flax used for a light (money, like tow, ‘burns’ fast)]

money.

[UK]Flash Dict. in Sinks of London Laid Open 128: Towe. clipt money.
[US]Schele De Vere Americanisms 296: Money itself has in the United States, as in England, probably more designations than any other object – liquor alone excepted [...] tow, wad (both of them evidently tailors’ slang).

In phrases

in tow

(Aus. prison) susceptible to bribery.

[Aus]Tupper & Wortley Aus. Prison Sl. Gloss. [Internet] Tow. As in ‘has a screw in tow’; where a prisoner has managed to organise a prison officer to traffic drugs or contraband into a prison.