I think you can find good relievers (not great) pretty cheap and pretty easily. Trade throw ins, waiting a bit during FA, comparitively cheap Internationals, etc.
AlexFox came as a trade throw in really. He was REALLY cheap and is pretty good. 1.12 WHIP/2.42 ERA 56/74 on splits But throws 83 on GBs and has an 85 1st pitch.
JulianFurcal is a stud type guy....but I waited a bit in FA and got him for $3.3 and $3.0 for two years. WHIP under 1.19 the last 5 years. Throws 100+ innings. He was a nice purchase.
PeterShin came as an Int. FA. Got him for $1.5M. Will be a bargain. Will be in the MLB pen next year...maybe later this year. AA/AAA WHIP of 1.1 and ERA of 2.00. Control is low, but with splits of (next year) 60-84 (est) and one pitch over 80 and another close...he'll be a fine reliever. He's the kind of guy you can steal in Int. FA.
RandallColes came in a multi-player trade. He'll be fine, next year.