I don't believ there is as what you are searchig for is some tool which could potentially predict the market which is by far heavy job and really hard one. You could look at graph price analisys to try to determen good price but even that is not 100% due to prices being manipulated every day. You don't know when will some coin have good contract or not. If you are going to dubt yourself either way why not simply buy now? There could be opportinities to get ETH and XMR at better rates but you never know.