Well, it depends on your budget and the exact type of data you are looking for. For instance, if you're looking for historical US-centric market data, try algoseek.
If you're looking for an inexpensive option then renting algoseek futures data through QuantGo is worth a try. If you prefer purchasing it directly, (as far as I remember) the cost would be around $500 for 10 years of history of their trade-based minute bar data.