A cleric who takes Vow of Poverty (Book of Exalted Deeds) can't carry a holy symbol. This is both true under the rules-as-written (he is allowed no material possessions except simple weapons, simple clothes, a spell component pouch and a sack containing day's food), and also confirmed by explicit Wizards of the Coast commentary in Vow of Poverty, Part 2:
[Classes for which] You Can Make [Vow of Poverty] Work, But It's a Big Handicap: [...] Clerics have a lot of spells with divine foci, so it's hard to avoid them. Paladins and clerics cannot turn undead without a holy symbol.
This prevents him from turning undead or casting any spells requiring Divine Focus, which is most spells.
A reasonable DM would allow a cleric to carry the 1-gp wooden holy symbol, but that's technically a house rule, not a standard rule.
Within the official rules (which for the purposes of this question I define as any D&D 3.0 or 3.5 content either published by Wizards of the Coast, or appearing in Dragon or Dungeon magazine), is there any way for a Vow of Poverty cleric, without breaking his vow, to carry and use a holy symbol, or otherwise to cast spells requiring Divine Focus, or to turn undead?