That's a 'how long is a piece of string?' question. No two coins are the same, some dates are more desirable than others and some denominations are more desirable than others. Coupled with the fact that not all desirable dates for one denomination are the same as those for a different denomination and you can easily see that there is no straightforward answer. The first thing you need to do is acquaint yourself with grades and grading. Get some experience in grading coins and see what they sell for when compared with references such as CCGB or Spink. ebay is not the best indicator of pricing because too many things sell for far more than they should and conversely so. In the case of pennies and farthings, 1849 is a good starting point, though you might take a while to get out of the blocks. Obviously the price to buy for needs to be lower than a selling price, but things starting at an elevated price on ebay frequently don't sell because most buyers are greedy. They want everything for 99p and consequently most will disregard the £100 coin priced at £75 BIN because they live in hope that the seller will give up trying to realise a decent price and offer them the chance of a real steal rather than a bargain. okay i shall have a good trawl through 1849 thanks for the advice my i aask what CCGB is an SPINK ?