All these services??

I see all of these linking services promoted here and am wondering what works ? The layered linking , link wheels, slow drip, etc.
What are some thoughts on what seems to be the best approach or a little of each? The services can add up in cost so trial and error could get pricey.
thanks in advance

The service that works is the one that does what you want to do in YOUR seo strategy. You would be wrong to just pick a strategy which you have not thought through. For example, if YOUR strategy is to do social media, link layering, a bit of blackhat, then you need to choose the services that provide this for you.

But depending on one service completely and not thinking through its effects, is not advisable. So before you buy, think about what you wish to do. Then from that, pick the services that help you achieve your goals.

A lot of different services could help your site. It depends a lot on what type of site you're making. If it's BH and you don't care if it only ranks for a month, then get as many links as you can, as fast as you can, from as many different places as you can. If it's a site you care about, then going with a higher quality link, at a slower pace is going to be a better idea. Pick the service that fits what you are doing, and even better than that, learn to build your own links.

Reach out to them, explain your situation and get advice, I always take peoples willingness to help into consideration before paying for a service.