Look up riggs wrangler jeans on amazon. They are around $30 or so, its definitely expensive but if you get set that has reinforced knees they should hold up for a while especially if you insert knee pads ( like a thin piece of foam) and should hold up for a while. (https://www.amazon.com/Workwear-Wrangler-Utility-Antique-Indigo/dp/B000A2KB5C/ref=sr_1_23?s=apparel&ie=UTF8&qid=1518054150&sr=1-23&nodeID=7141123011&psd=1&keywords=Riggs+Workwear)
cant break thse boots, the soles tend to devolpe a small crack after 3 years where your foot bends. the laces never broke nor have anything else ripped off or anything, solid built boots, once you use them youll never buy another type of work boot, the jeans are wrangler riggwear, theyre double layered up front so if they ge a hole or tear the bottom layer will still cover you, never had these split open from the crotch, they last about 2 years of everyday use https://www.amazon.com/Workwear-Wrangler-Utility-Antique-Indigo/dp/B000A2KB5C?pd_rd_w=H1aAv&pf_rd_p=a92e0124-cfa8-4f1e-82b5-a4a348d97008&pf_rd_r=7HN7XHDAP1CYKX31MF20&pd_rd_r=08fce943-3ba6-4d96-b393-986a03b8261b&pd_rd_wg=y75Ew&pd_rd_i=B000A2KB5C&psc=1&ref_=pd_bap_d_rp_5_i