Increase Cunning to at least 25, and buy at least two ranks of Stealing, before completing The Grey Wardens' Cache. Pick every pocket you can (twice per target at Ostagar).
Selling off everything short of basic equipment - especially with lucky corpse-loot and save/reload strategies for better theft results and container contents - should leave you with at least enough money for your first Spellward.
Dwarf Noble Rogue + DLC route: As above, but selling Blood Dragon Plate and Blightblood will help ensure you have enough gold by the end of Lothering (and even some extra spending money).
xbox360Players in particular may not want to lose the Blood Dragon Plate so early, as it is a superior version of the armor featuring significantly better bonuses than on the other platforms.
Any Origin/Class + exploit method: Traps are a Girl's Best Friend can be used to generate the needed gold - there is an exploit allowing it to be repeated endlessly. The drawback in this case is how far the current party will level up in the process, as 100 XP are gained with every 50 (minus materials cost).