Home high throughput cluster/computer

I would like to build a small cluster or a fast computer for hobby/educational purposes and to speedup my data processing/machine learning pipelines (so not 50 raspberypies). Things I am using now are cpu bound, I never used anything that can utilize CUDA, but it sounds like fun and I am not against it. I currently own one i5 old laptop with a broken screen, I was thinking about buying few more of similar laptops to make a small cluster or to use same money and actually build a workstation. I have peripherals but no other computer parts. I would like to spent around 1000 eur but have a possibility to spent more if I would want to/need to.

I think that for a cluster of laptops I can find good deal on some used ones, especially if they have some broken parts that are however not essential for computing (screen, wifi, touchpad etc). It also has a benefit of managing my own cluster and some cool factor. However laptops might have problems with memory and one machine might be more efficient with allocating resources and maybe even used for gaming (however I don't play that much so it's not a factor) or CUDA

What can give me more power for a buck? Any other suggestions/things to consider? Also, I don't want to require a power plant to use it

My problem with clustering is if you dont already own the computers usually spending more more money on older hardware to try and achieve higher performance and not wanting it to draw alot of power kind of contradict each other. you said you had an i5 laptop so I'm going to assume its a duel core laptop so I put a 12 core possessor in this build which should net you pretty good processing power I also put in a 2gb gtx 960 for CUDA but it isn't the 4 gb addition because gaming wasn’t a main priority.

Well you could go with 2 FX 8 core PCs

PCPartPicker part list: http://de.pcpartpicker.com/p/9BfKCJ
Price breakdown by merchant: http://de.pcpartpicker.com/p/9BfKCJ/by_merchant/

CPU: AMD FX-8320E 3.2GHz 8-Core Processor (€129.03 @ Mindfactory)
Motherboard: Gigabyte GA-970-Gaming ATX AM3+ Motherboard (€91.36 @ Mindfactory)
Memory: G.Skill Ares Series 32GB (4 x 8GB) DDR3-1600 Memory (€134.73 @ Mindfactory)
Video Card: XFX Radeon HD 5450 1GB Video Card (€30.54 @ Amazon Deutschland)
Power Supply: Super Flower Golden Green HX 350W 80+ Gold Certified ATX Power Supply (€54.90 @ Caseking)
Total: €440.56
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-03-30 19:56 CEST+0200