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You can use pumice stone found in any half-decent pharmacy or wet-dry sand-paper on a flat block (but I'm not sure about the grit).

Norton 4/8k should be enough for starters, especially since you're on a budget. Later, if you REALLY have $$$ to blow, get the 12K. However, I'd get the 220/1k before the 12K if you'll be dealing...