The price you ready to buy depends on how the market looks then and up to then i.e. are there tendencies for price drops or not, how has the market behaved and what does it look like it may be like in the next few days.

Other factors to consider are the investment period long-/short-term? If the former then as long as you think the price goes up you should be fine entering at a reasonable price. The entry point becomes more relevant when going for short-term.